The number and variety of songbirds peak during two periods across the Temperate Zone of eastern North America. From mid April to mid May and from mid September to mid October, we enjoy the largest mix of permanent residents, summer songbirds, seasonal migrants and, at the colder extremes of those intervals, winter songbird residents.
Typical permanent residents include cardinals, blue jays, tufted titmice, chickadees, robins, eastern bluebirds, cedar waxwings, Carolina wrens, white-breasted nuthatches, American goldfinches, eastern meadowlarks, song sparrows and a variety of woodpeckers. Among our common summer residents are house wrens, blue-gray gnatcatchers, ruby-throated hummingbirds, various swallows, chimney swifts, common nighthawks, indigo buntings, northern orioles, gray catbirds, brown thrashers, scarlet and summer tanagers and a host of summer warblers, sparrows and flycatchers. Pure migrants are primarily limited to northern warblers, ruby-crowned kinglets and certain vireo and flycatcher species while dark-eyed juncos, brown creepers, yellow-bellied sapsuckers, red-breasted nuthatches, yellow-rumped warblers, golden-crowned kinglets and a number of winter sparrows may be encountered from mid October to mid April.
While the above lists are incomplete, they illustrate the wide variety of songbirds that inhabit or move through our region in the course of a year. Novice birders hoping to maximize their sightings are advised to visit a diversity of habitat (forest, wetlands, meadows) and to plan their excursions for the early morning and late daylight hours, when these birds tend to be most active and conspicuous.
Thursday, September 13, 2012
Tuesday, September 11, 2012
Voyeurs of Tragedy
Every year, on the days surrounding September 11, American television programming revisits the horror of 2001 with documentaries, docudramas and replayed coverage of the terrorist attacks in New York, Pennsylvania and Washington DC. This annual obsession with reliving that tragic event, as if we need to be reminded of the details, is touted as a public service, an acknowledgement that terrorism still stalks the globe and a means to honor those who died in the carnage.
Yet, like all television programming, it is served up with the primary purpose of attracting viewers and, as media executives know, humans are perversely attracted to the specter of tragic events. Just as crowds gather to watch a jumper on a ledge or tune in to learn every detail about a mass shooting, they long to hear desperate phone calls from the Twin Towers and, for the hundredth time, to watch airliners slam into the World Trade Center.
Do we honor the dead with this programming or do we merely satisfy the sadistic voyeurism of the human animal? Can we not commemorate the historic tragedy without injecting it with the morbid curiosity of those who gawk at the plight of its victims? We have already used that horrific event to justify eleven years of senseless combat which has taken many more innocent lives; need we also be entertained by the suffering and death of the September 11 attacks?
Yet, like all television programming, it is served up with the primary purpose of attracting viewers and, as media executives know, humans are perversely attracted to the specter of tragic events. Just as crowds gather to watch a jumper on a ledge or tune in to learn every detail about a mass shooting, they long to hear desperate phone calls from the Twin Towers and, for the hundredth time, to watch airliners slam into the World Trade Center.
Do we honor the dead with this programming or do we merely satisfy the sadistic voyeurism of the human animal? Can we not commemorate the historic tragedy without injecting it with the morbid curiosity of those who gawk at the plight of its victims? We have already used that horrific event to justify eleven years of senseless combat which has taken many more innocent lives; need we also be entertained by the suffering and death of the September 11 attacks?
Afterlife Adventures
As my family has been instructed, I will be cremated upon my death and my ashes will be scattered in the Mt. Evans Wilderness Area, west of Denver. After that, who knows where I'll end up?
Perhaps a harsh winter will leave my remains entombed beneath a snow bank for several years, eventually providing nourishment for a young bristlecone pine. Absorbed by that long-lived tree, I may be part of its gnarled trunk for a thousand years or more, eventually re-entering the soil when the pine dies and crumbles. Now nourishing the grass of a mountain meadow, I could be consumed by a snowshoe hare and thence by a lynx or a golden eagle. Upon that predator's death, I would return to the wilderness, perhaps later flushed into the watershed of the South Platte via its North Fork, Bear Creek or Clear Creek. If not trapped in one of many reservoirs en route, I'll make my way down the Missouri, entering the Mississippi at St. Louis and then float down to the Gulf of Mexico. If caught up in the coastal marshes, I might be consumed by a wintering snow goose and then transported to the Arctic tundra for the summer. If not, I may swirl about the Gulf for a few years before drifting into the Caribbean and then out to sea. The Gulf Stream might deposit some of my remains on the shores of Iceland or the British Isles or, like Jonah, I might end up in the belly of a massive cetacean, stored in its blubber for decades. Eventually, after succumbing to humans, killer whales or old age, its carcass will rot on the ocean floor and I'll re-enter the marine ecosystem. Who knows, maybe a combination of ocean currents and tropical storms will transport my remnants to an exotic shore where, eons hence, compression, volcanism and uplift will place me atop another mountain range.
Of course, I could opt for embalming fluid and a cozy metal box beneath a manicured lawn. But why miss the adventure of nature's enduring cycle?
Perhaps a harsh winter will leave my remains entombed beneath a snow bank for several years, eventually providing nourishment for a young bristlecone pine. Absorbed by that long-lived tree, I may be part of its gnarled trunk for a thousand years or more, eventually re-entering the soil when the pine dies and crumbles. Now nourishing the grass of a mountain meadow, I could be consumed by a snowshoe hare and thence by a lynx or a golden eagle. Upon that predator's death, I would return to the wilderness, perhaps later flushed into the watershed of the South Platte via its North Fork, Bear Creek or Clear Creek. If not trapped in one of many reservoirs en route, I'll make my way down the Missouri, entering the Mississippi at St. Louis and then float down to the Gulf of Mexico. If caught up in the coastal marshes, I might be consumed by a wintering snow goose and then transported to the Arctic tundra for the summer. If not, I may swirl about the Gulf for a few years before drifting into the Caribbean and then out to sea. The Gulf Stream might deposit some of my remains on the shores of Iceland or the British Isles or, like Jonah, I might end up in the belly of a massive cetacean, stored in its blubber for decades. Eventually, after succumbing to humans, killer whales or old age, its carcass will rot on the ocean floor and I'll re-enter the marine ecosystem. Who knows, maybe a combination of ocean currents and tropical storms will transport my remnants to an exotic shore where, eons hence, compression, volcanism and uplift will place me atop another mountain range.
Of course, I could opt for embalming fluid and a cozy metal box beneath a manicured lawn. But why miss the adventure of nature's enduring cycle?
Monday, September 10, 2012
A Birding Trifecta
As an avid birder, I have been fortunate to live in a number of fabulous birding areas over the years and, as I near retirement, we own property in three of the best. Our home in central Missouri sits at the crossroads of bird migration in the U.S., hosting huge flocks of waterfowl in spring and fall, joined by American white pelicans, double-crested cormorants and many other water birds. In addition, most birds that are seasonal residents in or regular migrants through the Temperate latitudes of eastern North America can be observed in this region.
Our Littleton, Colorado, farm sits near the foothills of the Front Range, offering access to five life zones within an hour's drive. While birds unique to western foothills, mountain forests, alpine tundra and canyons are the obvious highlights, especially for visiting birdwatchers, the regional birding opportunities extend across the Piedmont and High Plains as well, including the seasonal presence of species such as mountain plovers, lark buntings, various longspurs, avocets, migrant shorebirds, sandhill cranes, bald eagles, white-faced ibis and a rich diversity of waterfowl that one might not expect to find in that semiarid landscape. Finally, our condo on Longboat Key, Florida, looks out on Sarasota Bay with its spectacular variety of birdlife, including waders, anhingas, gulls, terns, ospreys, brown pelicans and wintering waterfowl, not to mention the shorebirds and seabirds on the Gulf beaches and the colorful songbirds that inhabit the mangroves and tidal creeks. Short drives into the South Florida peninsula provide additional opportunities to observe caracaras, burrowing owls, Florida sandhill cranes, Florida scrub jays and other subtropical species. Spending parts of the year in all three locations, I enjoy a birding trifecta that provides exposure to a fabulous diversity of natural habitat, each with its unique population of flora and fauna.
Of course, every region of this magnificent Continent hosts an interesting variety of resident and migrant birds, many of which cannot be found near our properties. What better excuse to visit the northern coasts, the Great Lakes region and the Desert Southwest?
Our Littleton, Colorado, farm sits near the foothills of the Front Range, offering access to five life zones within an hour's drive. While birds unique to western foothills, mountain forests, alpine tundra and canyons are the obvious highlights, especially for visiting birdwatchers, the regional birding opportunities extend across the Piedmont and High Plains as well, including the seasonal presence of species such as mountain plovers, lark buntings, various longspurs, avocets, migrant shorebirds, sandhill cranes, bald eagles, white-faced ibis and a rich diversity of waterfowl that one might not expect to find in that semiarid landscape. Finally, our condo on Longboat Key, Florida, looks out on Sarasota Bay with its spectacular variety of birdlife, including waders, anhingas, gulls, terns, ospreys, brown pelicans and wintering waterfowl, not to mention the shorebirds and seabirds on the Gulf beaches and the colorful songbirds that inhabit the mangroves and tidal creeks. Short drives into the South Florida peninsula provide additional opportunities to observe caracaras, burrowing owls, Florida sandhill cranes, Florida scrub jays and other subtropical species. Spending parts of the year in all three locations, I enjoy a birding trifecta that provides exposure to a fabulous diversity of natural habitat, each with its unique population of flora and fauna.
Of course, every region of this magnificent Continent hosts an interesting variety of resident and migrant birds, many of which cannot be found near our properties. What better excuse to visit the northern coasts, the Great Lakes region and the Desert Southwest?
Sunday, September 9, 2012
Season of the Hunter
On these chilly, dark, early mornings of September, Orion reappears in the southern sky. Though this well-known constellation is a visual illusion, a product of our unique perspective from planet Earth, early man saw a hunter in that group of stars.
Of course, their interpretation was surely influenced by the season of its presence, stretching from the first chill of late summer through the long, cold, trying nights of winter, when Orion shines through the dry, clear, frigid air. They likely welcomed this hunter as a sign that massive flocks of waterfowl and migrant herds of herbivores would soon arrive from the north, providing sustenance through the lean months of winter. In this respect, Orion was both a promise of bounty and a warning of the coming hardship and, since they relied on hunting for their own survival, he was a cherished companion.
Today, equipped with the modern convenience of supermarkets, we may be less enamored with the hunter's appearance, knowing that the slide toward winter has quickened. But, for those of us who relish the crisp, colorful days of autumn and the invigorating chill of winter, Orion is a welcome sight in the southern sky. For prey species, the season of the hunter is far less rewarding as predators gain a distinct advantage amidst the barren forests, windswept plains and frozen wetlands.
Of course, their interpretation was surely influenced by the season of its presence, stretching from the first chill of late summer through the long, cold, trying nights of winter, when Orion shines through the dry, clear, frigid air. They likely welcomed this hunter as a sign that massive flocks of waterfowl and migrant herds of herbivores would soon arrive from the north, providing sustenance through the lean months of winter. In this respect, Orion was both a promise of bounty and a warning of the coming hardship and, since they relied on hunting for their own survival, he was a cherished companion.
Today, equipped with the modern convenience of supermarkets, we may be less enamored with the hunter's appearance, knowing that the slide toward winter has quickened. But, for those of us who relish the crisp, colorful days of autumn and the invigorating chill of winter, Orion is a welcome sight in the southern sky. For prey species, the season of the hunter is far less rewarding as predators gain a distinct advantage amidst the barren forests, windswept plains and frozen wetlands.
Friday, September 7, 2012
The Edge of Autumn
Sitting in my office this afternoon, I am looking out at a wall of dark clouds, pushing in from the west. Studded with thunderstorms, this front is the edge of autumn, promising a night of rain followed by the first glorious day of fall-like weather. Our overnight low is expected to dip near 50 degrees F and tomorrow's sunshine will only produce an afternoon high in the mid seventies; both of those extremes will be twenty degrees cooler than what we have averaged over the past few months.
Nearly upon us, the dark clouds look menacing but their trigger, a cool, dry Canadian air mass, is dropping south behind them. Assuming we avoid damaging winds and destructive hail, the heavy rains along the front will be more than welcome and the autumn air that plunges in their wake will provide the first convincing evidence of seasonal change.
No doubt, summer will battle back in the coming weeks but this sudden strike by old man winter is a powerful blow from the north, a welcome invasion across the parched landscape of America's Heartland. Darkness is now gathering at mid afternoon, lightening is flashing across the western horizon, shelf clouds are racing above Columbia and autumn's violent debut is at hand.
Nearly upon us, the dark clouds look menacing but their trigger, a cool, dry Canadian air mass, is dropping south behind them. Assuming we avoid damaging winds and destructive hail, the heavy rains along the front will be more than welcome and the autumn air that plunges in their wake will provide the first convincing evidence of seasonal change.
No doubt, summer will battle back in the coming weeks but this sudden strike by old man winter is a powerful blow from the north, a welcome invasion across the parched landscape of America's Heartland. Darkness is now gathering at mid afternoon, lightening is flashing across the western horizon, shelf clouds are racing above Columbia and autumn's violent debut is at hand.
Thursday, September 6, 2012
Costa Rica's Earthquake
Yesterday's earthquake off the west coast of Costa Rica occurred along a subduction zone where the Cocos Plate is dipping beneath the Caribbean Plate. A remnant of the Farallon Plate, like the Juan de Fuca Plate off the Pacific Northwest and the Nazca Plate off South America, the Cocos Plate lies along the west coast of southern Mexico and Central America. At its western edge, this Plate is both forming and diverging from the Pacific Plate along the East Pacific Rise, a mid oceanic ridge; shoved eastward, it is forced to subduct beneath the more buoyant Caribbean Plate. As it dips toward the mantle, the leading edge of the Cocos Plate melts, producing a chain of volcanoes east of the subduction trench (along the west coast of Mexico and Central America).
Subduction zone earthquakes generally result from a sudden slippage of the overriding plate; in this case, the western edge of the Caribbean plate was pulled down by friction with the dipping Cocos Plate and suddenly rebounded upward. Since subduction zones most often occur along coastlines, this upward motion of the overriding plate (usually a continental plate margin) also displaces the overlying seawater, potentially triggering a tsunami.
Fortunately, yesterday's magnitude 7.6 quake did not spawn a tsunami though its tremors were felt from Nicaragua to Panama. The strongest earthquake to strike Costa Rica in more than twenty years, it will almost certainly be followed by a series of aftershocks as pressure is transferred down the fault lines. In some cases, such subduction quakes also reignite volcanoes that rise along the adjacent coast. Those who live along subduction corridors thus face the triple threat of earthquakes, volcanism and tsunamis.
Subduction zone earthquakes generally result from a sudden slippage of the overriding plate; in this case, the western edge of the Caribbean plate was pulled down by friction with the dipping Cocos Plate and suddenly rebounded upward. Since subduction zones most often occur along coastlines, this upward motion of the overriding plate (usually a continental plate margin) also displaces the overlying seawater, potentially triggering a tsunami.
Fortunately, yesterday's magnitude 7.6 quake did not spawn a tsunami though its tremors were felt from Nicaragua to Panama. The strongest earthquake to strike Costa Rica in more than twenty years, it will almost certainly be followed by a series of aftershocks as pressure is transferred down the fault lines. In some cases, such subduction quakes also reignite volcanoes that rise along the adjacent coast. Those who live along subduction corridors thus face the triple threat of earthquakes, volcanism and tsunamis.
Wednesday, September 5, 2012
Shuttle vs. Trees
In order to transport the Space Shuttle Endeavour to its new home in Los Angeles, some 400 trees will be destroyed along its final glide path. While a promise has been made to replace them with twice as many young trees, the loss of the large, older shade trees has outraged many citizens.
Regardless of one's view on this matter, the decision illuminates man's tendency to place a higher priority on technology and development than on conservation. The Endeavour, a powerful symbol of human achievement, will be paraded past an adoring public; in preparation, nature's handiwork will be sacrificed. Of course, the financial benefits of the shuttle shrine will be reaped for generations to come and, as we all know, economics trumps nature in human society.
A more subtle revelation of this decision is our preoccupation with the past, often at our own expense. We excel at commemoration but are less adept at planning for the future. In our rush to glorify the past and to make our present life more enjoyable, we fail to address the long-term effects that our policies might have on the welfare of this planet.
Regardless of one's view on this matter, the decision illuminates man's tendency to place a higher priority on technology and development than on conservation. The Endeavour, a powerful symbol of human achievement, will be paraded past an adoring public; in preparation, nature's handiwork will be sacrificed. Of course, the financial benefits of the shuttle shrine will be reaped for generations to come and, as we all know, economics trumps nature in human society.
A more subtle revelation of this decision is our preoccupation with the past, often at our own expense. We excel at commemoration but are less adept at planning for the future. In our rush to glorify the past and to make our present life more enjoyable, we fail to address the long-term effects that our policies might have on the welfare of this planet.
Tuesday, September 4, 2012
First Migrant Songbird
Yesterday evening, a female magnolia warbler was flitting about the lower branches of our black maple. It was the first migrant songbird that I have observed this season, to be followed by many more from now until mid October. Staying ahead of the autumn chill, which will suppress if not kill off her insect prey, she is headed for a balmy winter in Central America. After enduring the excessive heat this summer, I do not envy her journey.
Named for the fact that they were first scientifically observed and classified in a grove of southern magnolias, during their migration, magnolia warblers actually nest in open coniferous forests across central and eastern Canada, the Great Lakes Region, New England and along the Appalachian Chain, as far south as Virginia. Come late summer, they head for wintering grounds in Central America and the West Indies. Attractively colored with a mix of gray, white, black, yellow and olive plumage, magnolia warbers are common migrants throughout the eastern half of the U.S. and are relatively easy to observe since they tend to feed in shrubs and in the lower branches of shade trees.
While some shorebirds begin their "autumn migration" by July, the songbird migration generally runs from early September to mid October, led by the dedicated insectivores such as common nighthawks, warblers and gnatcatchers. Toward the end of their migration period, the fair weather migrants and summer residents are replaced by hardy winter songbirds, arriving from northern latitudes to spend the cold, gray months in the balmy Temperate Zone. This year, drained by the long, hot summer, I can't wait to welcome them.
Named for the fact that they were first scientifically observed and classified in a grove of southern magnolias, during their migration, magnolia warblers actually nest in open coniferous forests across central and eastern Canada, the Great Lakes Region, New England and along the Appalachian Chain, as far south as Virginia. Come late summer, they head for wintering grounds in Central America and the West Indies. Attractively colored with a mix of gray, white, black, yellow and olive plumage, magnolia warbers are common migrants throughout the eastern half of the U.S. and are relatively easy to observe since they tend to feed in shrubs and in the lower branches of shade trees.
While some shorebirds begin their "autumn migration" by July, the songbird migration generally runs from early September to mid October, led by the dedicated insectivores such as common nighthawks, warblers and gnatcatchers. Toward the end of their migration period, the fair weather migrants and summer residents are replaced by hardy winter songbirds, arriving from northern latitudes to spend the cold, gray months in the balmy Temperate Zone. This year, drained by the long, hot summer, I can't wait to welcome them.
Monday, September 3, 2012
Morning Stress
As we awaken from the deep chasm of sleep, interrupted though it might have been by a series of dreams, the natural stress hormones of our body begin to peak, preparing us to face the challenges of life. For early man, this biochemical reaction may have been especially vital, susceptible as he was to predators, storms and the other threats of nature. Stoking his awareness and capacity for flight, cortisol and other hormones assured a rapid transition from the inertia of sleep.
While this natural process may be less crucial today, its effects remain and, at times, may have negative consequences. Dragged from the carefree world of sleep into the reality of our modern life, we are suddenly flooded with problems that we managed to ignore throughout the night. Recent turmoil, current demands, chronic worries and looming threats all come streaming into conciousness, raising our level of stress to what is often its highest point in the course of a day. Indeed, medical studies have often demonstrated a high incidence of myocardial infarction (commonly known as a heart attack) during the early morning hours.
Awareness of this natural human trait is the key to avoiding its consequences. Should you awaken and find yourself suddenly overwhelmed by the demands of the coming day or week, remind yourself that this is morning stress and conciously choose to ignore those problems for an hour or two. By then, your biochemical engine will begin to cool down and a more reasoned approach to their solutions will become apparent. As with most health-related issues, we have a good deal of control over the negative effects of this natural stress response.
While this natural process may be less crucial today, its effects remain and, at times, may have negative consequences. Dragged from the carefree world of sleep into the reality of our modern life, we are suddenly flooded with problems that we managed to ignore throughout the night. Recent turmoil, current demands, chronic worries and looming threats all come streaming into conciousness, raising our level of stress to what is often its highest point in the course of a day. Indeed, medical studies have often demonstrated a high incidence of myocardial infarction (commonly known as a heart attack) during the early morning hours.
Awareness of this natural human trait is the key to avoiding its consequences. Should you awaken and find yourself suddenly overwhelmed by the demands of the coming day or week, remind yourself that this is morning stress and conciously choose to ignore those problems for an hour or two. By then, your biochemical engine will begin to cool down and a more reasoned approach to their solutions will become apparent. As with most health-related issues, we have a good deal of control over the negative effects of this natural stress response.
Sunday, September 2, 2012
September Spring
Isaac's rains have spawned a September spring across central Missouri as dry, brown lawns and drooping vegetation have been reinvigorated by the abundant moisture. Greenery is returning to the parched landscape, birds seem energized by the cool, damp weather and the winter-like death grip of our intense summer heat has, for now, been broken.
Indeed, deprived of moisture and wilted by the unrelenting sun, the vegetation of our State, while not completely decimated, had entered a state of estivation, dropping leaves and fruit to retain water in more vital tissues of the stems and roots. Creeks and ponds, normally teeming with life during the verdant days of summer, had given way to dry, rocky beds and cracked mudflats, depriving many insects, tadpoles and fish of crucial spawning and maturation habitat and, in turn, upsetting the food chain for primary and secondary consumers. How the dry, stressed vegetation affected populations of resident herbivores and their predators remains to be seen.
Of course, the brutal summer had an impact on humans as well, causing many to retreat to air-conditioned shelters for weeks at a time. With no grass to cut or shrubs to trim, yard work was confined to watering gardens and removing dead vegetation. Few cared to visit parks or nature preserves in the intense heat, especially since the parched landscape had little appeal and the wild residents were inconspicuous, having escaped to cool, secluded woodlands. Now, thanks to Isaac, we, like the plants and wildlife, are revived by the September spring, determined to relish the great outdoors before winter arrives to suppress nature's bounty once again.
Indeed, deprived of moisture and wilted by the unrelenting sun, the vegetation of our State, while not completely decimated, had entered a state of estivation, dropping leaves and fruit to retain water in more vital tissues of the stems and roots. Creeks and ponds, normally teeming with life during the verdant days of summer, had given way to dry, rocky beds and cracked mudflats, depriving many insects, tadpoles and fish of crucial spawning and maturation habitat and, in turn, upsetting the food chain for primary and secondary consumers. How the dry, stressed vegetation affected populations of resident herbivores and their predators remains to be seen.
Of course, the brutal summer had an impact on humans as well, causing many to retreat to air-conditioned shelters for weeks at a time. With no grass to cut or shrubs to trim, yard work was confined to watering gardens and removing dead vegetation. Few cared to visit parks or nature preserves in the intense heat, especially since the parched landscape had little appeal and the wild residents were inconspicuous, having escaped to cool, secluded woodlands. Now, thanks to Isaac, we, like the plants and wildlife, are revived by the September spring, determined to relish the great outdoors before winter arrives to suppress nature's bounty once again.
Saturday, September 1, 2012
Swamp Cooler
After a long, brutal summer, enveloped in hot, dry air, we in Missouri are now bathed by the remnants of Hurricane Isaac. The familiar humidity of the American Midwest has returned, exceeded now by the swampy feel of the Tropics. Moisture collects on windows and drips from plants and, even between showers, a fine mist hangs in the air.
Now near the center of Isaac's broad circulation, the wind is calm and low clouds hang above Columbia, trapping thick, balmy air near the surface. Though the copious moisture is subtropical in origin, it has broken the intense heat that persisted through most of the summer. Humid air is less dense than its dry, desert counterpart and cannot achieve the high temperatures that baked Missouri for the past few months. In addition, the process of condensation consumes heat, falling rain cools the air and the blanket of dense cloud cover reflects the solar radiation.
Our current swampy air is thus cooler than the dry air mass that is poised to return in the coming days. As the storm's center drifts off to the east, its backside moisture will give us a final dose of welcome rain before the heat and sunshine return. Fortunately, now that we are two months beyond the summer solstice, our longer nights should keep the intense summer heat at bay and, over the next few weeks, we will slip toward the mild, colorful days of autumn.
Now near the center of Isaac's broad circulation, the wind is calm and low clouds hang above Columbia, trapping thick, balmy air near the surface. Though the copious moisture is subtropical in origin, it has broken the intense heat that persisted through most of the summer. Humid air is less dense than its dry, desert counterpart and cannot achieve the high temperatures that baked Missouri for the past few months. In addition, the process of condensation consumes heat, falling rain cools the air and the blanket of dense cloud cover reflects the solar radiation.
Our current swampy air is thus cooler than the dry air mass that is poised to return in the coming days. As the storm's center drifts off to the east, its backside moisture will give us a final dose of welcome rain before the heat and sunshine return. Fortunately, now that we are two months beyond the summer solstice, our longer nights should keep the intense summer heat at bay and, over the next few weeks, we will slip toward the mild, colorful days of autumn.
Friday, August 31, 2012
Missouri Welcomes Isaac
As I walked to work, at 6 AM, the leading cloud bank from Isaac's massive pinwheel was drifting northward above Columbia. Ahead of that cloud layer was the yellow-pink sky of dawn, giving the impression that the sun was about to rise on the northern horizon.
By 8 AM, the first rain showers arrived from the south and, for the past four hours, a steady rain has been falling across central Missouri. Devoid of high winds or severe thunderstorms, this prolonged deluge is more than welcome in our parched State; if the current forecast is correct, we should enjoy intermittent precipitation through tomorrow afternoon, recharging the creeks, reinvigorating the plants and bringing our wetlands back to life. Though too late to salvage most of this year's crop production, Isaac should put a modest dent in our prolonged drought and, hopefully, rescue the hayfields and grasslands.
As of early afternoon, the storm's center sits along the extreme western segment of the Arkansas-Missouri border and we remain on its eastern side, receiving a steady stream of moisture from the Gulf of Mexico; indeed, on the radar, streamers of rain are still coming ashore along the Gulf Coast and plumes of precipitation stretch from Louisiana and Mississippi to northern Missouri and western Illinois. Over the next 24 hours, Isaac is forecast to drift northeastward, taking its moisture to the Ohio Valley and, eventually, to the Northeastern U.S. Though he wreaked havoc along the Gulf Coast, we will be sorry to see him go.
By 8 AM, the first rain showers arrived from the south and, for the past four hours, a steady rain has been falling across central Missouri. Devoid of high winds or severe thunderstorms, this prolonged deluge is more than welcome in our parched State; if the current forecast is correct, we should enjoy intermittent precipitation through tomorrow afternoon, recharging the creeks, reinvigorating the plants and bringing our wetlands back to life. Though too late to salvage most of this year's crop production, Isaac should put a modest dent in our prolonged drought and, hopefully, rescue the hayfields and grasslands.
As of early afternoon, the storm's center sits along the extreme western segment of the Arkansas-Missouri border and we remain on its eastern side, receiving a steady stream of moisture from the Gulf of Mexico; indeed, on the radar, streamers of rain are still coming ashore along the Gulf Coast and plumes of precipitation stretch from Louisiana and Mississippi to northern Missouri and western Illinois. Over the next 24 hours, Isaac is forecast to drift northeastward, taking its moisture to the Ohio Valley and, eventually, to the Northeastern U.S. Though he wreaked havoc along the Gulf Coast, we will be sorry to see him go.
Wednesday, August 29, 2012
The Meteorologist's Disclaimer
Meteorologists do not want human injuries or structural damage to result from the weather; after all, their job is primarily devoted to warning the public when dangerous conditions are expected to develop. Then again, they live for hurricanes, tornado outbreaks and blizzards, pouring over their sophisticated radar reports and willing to spend hours refining and explaining their data to weather junkies.
Who can blame them? After they spend weeks waving at fronts, urban temperatures and pressure gradients on a blue screen, severe weather gives them the chance to focus on storm dynamics and to perform for an attentive public. While most citizens are content to check the forecast in the morning paper or on the local news, the threat of dangerous storms drives them to the Weather Channel and other national programs for regular updates and, for those interested, at least a modest degree of scientific meteorology.
As a physician, I understand the enthusiasm that meteorologists have for severe weather events. Spending much of my time diagnosing and treating common maladies, I welcome the occasional life-threatening condition even though it is bad news for the patient; of course, I am often in a position to intervene while the weatherman has absolutely no control over Mother Nature. So, when meteorologists get excited about supercell thunderstorms and strengthening hurricanes while, for public consumption, expressing hope that they fall apart, I and others understand their mixed emotions.
Who can blame them? After they spend weeks waving at fronts, urban temperatures and pressure gradients on a blue screen, severe weather gives them the chance to focus on storm dynamics and to perform for an attentive public. While most citizens are content to check the forecast in the morning paper or on the local news, the threat of dangerous storms drives them to the Weather Channel and other national programs for regular updates and, for those interested, at least a modest degree of scientific meteorology.
As a physician, I understand the enthusiasm that meteorologists have for severe weather events. Spending much of my time diagnosing and treating common maladies, I welcome the occasional life-threatening condition even though it is bad news for the patient; of course, I am often in a position to intervene while the weatherman has absolutely no control over Mother Nature. So, when meteorologists get excited about supercell thunderstorms and strengthening hurricanes while, for public consumption, expressing hope that they fall apart, I and others understand their mixed emotions.
Tuesday, August 28, 2012
Delta Blues
Molded by the glaciers and meltwater torrents of the Pleistocene, the broad Mississippi River watershed stretches from the Rockies to the Appalachians. Over the past 2 million years, its major rivers and their numerous tributaries have carried vast amounts of sand and silt from the mountains, plains and Central Lowlands to the Gulf of Mexico, producing a massive delta of braided streams, coastal wetlands, tidal flats and sandbars. Home to a diverse assembly of wildlife, from fish to mollusks to waders and sea birds, this rich ecosystem has also attracted humans, first drawn by the abundant food supply and later by the access to America's interior.
After damming the major rivers and attempting to inhabit the Mississippi floodplain, protected by a network of canals and levees, we have altered the delta ecosystem and have placed ourselves at the mercy of nature's relentlous cycle of inland flooding and tropical storms. Deprived of nutrients and silt by the dams and levees, the Mississippi Delta has been shrinking for decades, offering less protection to other coastal habitats; in addition, sea level is rising in response to global warming and the Gulf of Mexico will gradually flood the remaining delta wetlands.
Today, seven years after Katrina wreaked havoc on the city of New Orleans, Isaac spins offshore, soon to arrive with its storm surge and torrential rains. Whether the expensive new levee system will protect the city remains to be seen but, once more, the folly of living on natural floodplains and wetlands has become apparent. Even before the storm damage is known, the costs of protection and evacuation are beginning to take a toll and, in the spirit of American politics, Governor Jindal is chiding President Obama for not doing enough. In what is otherwise a spectacular natural ecosystem, humans ensure that the Delta Blues will prevail.
After damming the major rivers and attempting to inhabit the Mississippi floodplain, protected by a network of canals and levees, we have altered the delta ecosystem and have placed ourselves at the mercy of nature's relentlous cycle of inland flooding and tropical storms. Deprived of nutrients and silt by the dams and levees, the Mississippi Delta has been shrinking for decades, offering less protection to other coastal habitats; in addition, sea level is rising in response to global warming and the Gulf of Mexico will gradually flood the remaining delta wetlands.
Today, seven years after Katrina wreaked havoc on the city of New Orleans, Isaac spins offshore, soon to arrive with its storm surge and torrential rains. Whether the expensive new levee system will protect the city remains to be seen but, once more, the folly of living on natural floodplains and wetlands has become apparent. Even before the storm damage is known, the costs of protection and evacuation are beginning to take a toll and, in the spirit of American politics, Governor Jindal is chiding President Obama for not doing enough. In what is otherwise a spectacular natural ecosystem, humans ensure that the Delta Blues will prevail.
Monday, August 27, 2012
The Sea of Cortez
During the Miocene Period, some 25 million years ago, rift volcanism began to develop in the region now occupied by extreme southeastern California, southwestern Arizona and northwestern Mexico. This rifting was triggered primarily by a northern extension of the East Pacific Rise, a mid oceanic ridge that stretches across the southeastern corner of the Pacific Ocean. Extensive faulting through this rift zone caused blocks of crust to drop below the adjacent terrain and, by 5 million years ago, the sea had invaded from the south. Augmented by the wet climate of the Pleistocene, the Colorado River swept enormous quantities of erosional debris into the northern end of this new sea, producing a vast delta that, today, obscures the connection of the Gulf of California Rift with faults of the Salton Trough and San Andreas network to its northwest.
Having torn the Baja Peninsula from mainland Mexico, this rifting, which continues today, transmitted pressure along the San Andrea Fault and across the landscape of Southern California, lifting fault block mountains and crumpling up the Transverse Ranges north of the Los Angeles Basin. Knifing into the southern portion of the Sonoran Desert, the Sea of Cortez (or Gulf of California) is lined with rich estuaries and marine wetlands, producing a dramatic contrast with the dry, cactus studded uplands that border its channel. The northern portion of the Sea, its basin partly filled by submarine layers of the Colorado River Delta, is much shallower and more saline than the central and southern regions. Numerous islands and islets rise above the surface of the Sea while rifting and volcanism persist in its deep channels, gradually widening the Gulf; eventually, the Baja will move off with Southern California, riding atop the Pacific Plate and destined for southwestern Alaska.
Among the most diverse and productive marine ecosystems on Earth, the Sea of Cortez has long been renowned for its rich fisheries, massive sea bird colonies and wide variety of resident and wintering cetaceans. Yet, despite the cooperative efforts of many regional and international conservation organizations, this young, fragile ecosystem is threatened by human activity; coastal wetland destrution, pollution and overfishing all take their relentless toll.
Having torn the Baja Peninsula from mainland Mexico, this rifting, which continues today, transmitted pressure along the San Andrea Fault and across the landscape of Southern California, lifting fault block mountains and crumpling up the Transverse Ranges north of the Los Angeles Basin. Knifing into the southern portion of the Sonoran Desert, the Sea of Cortez (or Gulf of California) is lined with rich estuaries and marine wetlands, producing a dramatic contrast with the dry, cactus studded uplands that border its channel. The northern portion of the Sea, its basin partly filled by submarine layers of the Colorado River Delta, is much shallower and more saline than the central and southern regions. Numerous islands and islets rise above the surface of the Sea while rifting and volcanism persist in its deep channels, gradually widening the Gulf; eventually, the Baja will move off with Southern California, riding atop the Pacific Plate and destined for southwestern Alaska.
Among the most diverse and productive marine ecosystems on Earth, the Sea of Cortez has long been renowned for its rich fisheries, massive sea bird colonies and wide variety of resident and wintering cetaceans. Yet, despite the cooperative efforts of many regional and international conservation organizations, this young, fragile ecosystem is threatened by human activity; coastal wetland destrution, pollution and overfishing all take their relentless toll.
Sunday, August 26, 2012
Never Mind!
For a week or more, many Americans, especially those in Florida, have been glued to the Weather Channel, anxiously awaiting every update on the progress of Tropical Storm Isaac. While the expected tragedy seems to be unfolding in Haiti, primarily due to inadequate shelters and infrastructure in that country, most other reports have involved minimal impact from the storm to date.
Meanwhile, from the Expert Desk, computer models have been unrolled on a regular basis and, for the past several days, had generally agreed on a path along the west coast of Florida. The only question was how severe the winds and storm surge would be and how disastrous Isaac would be for the Republican National Convention, in Tampa. A great deal of focus was also directed to the risk of tornadoes and torrential rain across the Sunshine State.
This morning, all has changed. The computer-generated cone of risk has shifted dramatically to the west, suggesting that the storm's impact across Florida (except for the Keys) may be limited and that the major threat (a Category 2 Hurricane) is now expected to impact the northern Gulf Coast, from New Orleans to Mobile. Jim Cantore, the Weather Channel's most recognizable celebrity and hurricane stuntman, initially assigned to ground zero (Tampa), will surely catch a flight to the revised impact zone and the hurricane forecast experts, focused on Florida for the past week, will be left to explain how their models were so unreliable. I suggest the immortal words of the late Rosanne Rosannadanna: Never Mind!
Meanwhile, from the Expert Desk, computer models have been unrolled on a regular basis and, for the past several days, had generally agreed on a path along the west coast of Florida. The only question was how severe the winds and storm surge would be and how disastrous Isaac would be for the Republican National Convention, in Tampa. A great deal of focus was also directed to the risk of tornadoes and torrential rain across the Sunshine State.
This morning, all has changed. The computer-generated cone of risk has shifted dramatically to the west, suggesting that the storm's impact across Florida (except for the Keys) may be limited and that the major threat (a Category 2 Hurricane) is now expected to impact the northern Gulf Coast, from New Orleans to Mobile. Jim Cantore, the Weather Channel's most recognizable celebrity and hurricane stuntman, initially assigned to ground zero (Tampa), will surely catch a flight to the revised impact zone and the hurricane forecast experts, focused on Florida for the past week, will be left to explain how their models were so unreliable. I suggest the immortal words of the late Rosanne Rosannadanna: Never Mind!
Friday, August 24, 2012
Hurricane Anxiety
On this 20th Anniversary of Hurricane Andrew's landfall in Greater Miami, all eyes are on Tropical Storm Isaac as it spins in the Caribbean. As of this morning, the storm seems to be losing its structure and now threatens the regional islands primarily with torrential rain. This could be a devastating development in the tent cities of Haiti, where deforestation poses a major risk of mudslides and flooding.
According to their latest forecast, the Hurricane Center still expects Isaac to pass over Cuba and then enter the Gulf of Mexico. If the storm does not fizzle over Cuba, the warm waters of the Gulf, combined with favorable upper level winds, may cause Isaac to strengthen into a hurricane along or near the west coast of Florida. Whether it moves NNW along the Gulf beaches of Florida or heads more northwesterly toward the north-central Gulf Coast remains uncertain.
Of course, those of us with property along the Gulf Coast hope that the storm remains offshore and does not strengthen. On the other hand, those of us in the drought-plagued Midwest hope that it comes ashore as a Tropical Storm and parks over our region for a week or so, bringing much needed moisture to the Heartland. Meanwhile, the Weather Channel has dispatched its fearless hurricane stuntmen along Isaac's projected path and is doing its best to keep us all informed, prepared and anxious.
According to their latest forecast, the Hurricane Center still expects Isaac to pass over Cuba and then enter the Gulf of Mexico. If the storm does not fizzle over Cuba, the warm waters of the Gulf, combined with favorable upper level winds, may cause Isaac to strengthen into a hurricane along or near the west coast of Florida. Whether it moves NNW along the Gulf beaches of Florida or heads more northwesterly toward the north-central Gulf Coast remains uncertain.
Of course, those of us with property along the Gulf Coast hope that the storm remains offshore and does not strengthen. On the other hand, those of us in the drought-plagued Midwest hope that it comes ashore as a Tropical Storm and parks over our region for a week or so, bringing much needed moisture to the Heartland. Meanwhile, the Weather Channel has dispatched its fearless hurricane stuntmen along Isaac's projected path and is doing its best to keep us all informed, prepared and anxious.
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