Friday, June 29, 2012

Life in the Universe

Current scientific evidence indicates that the Universe is 13.7 billion years old and that the galaxies formed 12 billion years ago.  Yet, our home star, the sun, is less than 5 billion years old, the Earth  formed just 4.6 billion years ago, unicellular life did not evolve on our planet until 3.6 billion years ago and we humans did not appear until 130,000 years ago.  Countless suns, their solar systems and the life that inhabited their planets likely evolved and disappeared long before our own sun and planet came into existence.

Among the 100 billion galaxies and trillions of stars that stretch across the ever-expanding Universe, there are surely millions of other planets that sustain life which, in many if not most cases, has progressed farther along the evolutionary tree than has life here on Earth.  In other words, it is almost a certainty that many human-like civilizations inhabit this Universe, most of which are more advanced than our own.

It is understandable that religious persons might find these rational facts too threatening to contemplate but it is disconcerting to hear scientists and scientific journalists question whether life exists elsewhere in the Universe.  Sitting here on our smallish planet that circles a modest-sized star on an outer band of a massive galaxy, it is absurd to suggest that we might be the only intelligent beings that inhabit the billions of galaxies.  The Universe surely teems with life and it is only our irrational self-importance that keeps us from embracing that fact.

Thursday, June 28, 2012

Desert Heat in the Midwest

Records are falling across the American Midwest this week as the first major heat wave of the season invades our region.  High pressure over the Southern Plains, combined with a high pressure dome over the Southeast, has ushered in the hot, dry air; afternoon highs should top 100 degrees F in most areas.

In part, the extreme heat reflects the dryness of the air, as Gulf of Mexico moisture is kept at bay by the blocking high across the Southeast.  Dry air is more dense than humid air and is thus capable of reaching higher temperatures.  Indeed, winds are from the west-southwest and it feels more like Phoenix than Miami across the Heartland.

This heat wave will be slow to break as cloudless skies permit the intense sunshine to heat up the roofs and roadways in our towns and cities; this heat radiates into the air overnight, keeping the morning low well above average.  In addition, it will likely take a strong cold front to displace this high pressure ridge and none are forecast over the coming week.  For now, we'll confine our outdoor activities to the early morning and evening hours, hide from the afternoon sun and dream of October.

Wednesday, June 27, 2012

Industrial Obesity

Not long ago, we humans could not help but get plenty of exercise.  We had to hunt and spend long hours in the fields to obtain our food.  We had to chop wood to heat our homes and carry fresh water from the well or the river.  Travel was by foot or horseback and almost any task involved physical labor.  Perhaps most significant, we did not have televisions or computers to keep us inactive and entertained for hours at a time.

While many studies have demonstrated a higher rate of obesity in westernized countries, much of the focus has been on the dietary changes associated with our mechanized cultures.  But, while the excessive intake of sodas and cheeseburgers and donuts should raise concerns about our nutrition, it is, in my opinion, a less significant factor in the modern scourge of obesity than is our sedentary lifestyle.

Today, almost every technological advancement is designed to make our lives easier.  We may take our morning or evening stroll to get some exercise but most of our day is spent in cars, elevators and desk chairs.  Even farmers and construction workers have a wide range of machinery and tools that limit their physical labor.  Then, at the end of the day, exhausted and stressed, we plop in front of the television for several hours of mindless entertainment, getting up for a snack during commercial breaks.

Tuesday, June 26, 2012

The Nature of Volcanism

Volcanoes develop in areas where the heat from Earth's mantle melts the overlying crust.  This occurs along subduction zones, where one of the tectonic plates is dipping toward the mantle, in rift zones, where the crust is thinning (allowing the mantle to move upward) and at hotspots, where a mantle plume is rising into the crust.

Subduction volcanoes are the most widespread form of volcanism on Earth and are concentrated along the Pacific Rim where the Pacific Plate and its associated oceanic plates are dipping beneath the South American, North American, Eurasian and Australian Plates.  The Andes, the volcanoes of western Central America and Mexico, the Cascades, the Aleutians and the volcanoes along the western edge of the Pacific (Japan, Taiwan, Philippines, New Zealand) result from this process.  Other subduction volcanoes include those along the western and southern edge of Indonesia, the volcanic islands of the eastern Caribbean and Mt. Etna, on Sicily, one of the most active volcanoes on our planet.

Rift volcanoes include those above mid-oceanic ridges and those developing along rift valleys in continental crust.  Most oceanic ridge volcanoes are well below the surface of the sea and thus not readily observed; the major exception is the island nation of Iceland, which formed (and continues to form) above the mid-Atlantic ridge.  Continental rift volcanoes are seen along and within the East African Rift and the Rio Grande Rift of the American Southwest; they are also scattered throughout the Great Basin of the U.S. where the crust is being stretched (and thinned).  Hotspot volcanism occurs across the globe, along the ocean floor and beneath/within continental crust; the Hawaiian Islands, the Galapagos Islands, the Canary Islands, Yellowstone, the San Francisco Peaks of northern Arizona and the volcanic field of northeastern New Mexico are but a few examples.

Monday, June 25, 2012

The Lena River Delta

On satellite imagery, the Lena River Delta on the northern coast of Siberia gives the appearance of a fan coral, its braided channels and numerous lakes forming an intricate pattern across the Arctic tundra.  It is this landscape of countless pools and waterways that attracts huge congregations of loons, grebes, shorebirds and waterfowl to this 11,600 square mile wetland to nest and raise their young during the brief Arctic summer.

The Lena River, the second largest stream in Siberia, rises a few miles west of Lake Baikal, flowing northward and gradually eastward for 2700 miles to its delta on the Laptev Sea.  There it delivers tons of sediment each year, gradually enlarging and enriching the delta which is also an important spawining area for Arctic fish.  Nesting birds of note include red-necked grebes, four species of loon, whooper and tundra swans, bean geese, black brant, king and Steller's eiders, long-tailed ducks, Ross's and Sabine's gulls and numerous shorebird species.  Of course, willow grouse, rock ptarmigan, snowy owls, peregrine falcons and a wide variety of Arctic songbirds also inhabit the delta.  Resident mammals include gray wolves, Arctic fox, wolverines, least weasels, stoats, lemmings, tundra voles and reindeer; beluga whales, walruses and a variety of seals often visit the area.

Fortunately, most of this vast tundra wetland is protected within the Lena River Delta Nature Reserve, the largest nature preserve in Russia.  Visited only by the most adventurous naturalists, this spectacular but remote site is relatively free of human disturbance; nevertheless, the Lena, like all rivers on our planet, is tainted by pollutants from agriculture, mining, industry and sewage and their long term effects on the delta ecosystem is yet to be determined.

Sunday, June 24, 2012

Dubious Debby

After forming in the eastern Gulf of Mexico over the past 48 hours, Tropical Storm Debby is going nowhere fast.  Parked west of Tampa and south of Panama City, she seems to be teasing the National Hurricane Center with her uncertain intentions.

The question is whether a weak cold front dropping through the Southeast will pick up the storm and shunt it northeastward, across Florida, or whether Debby will drift westward, gathering strength over the warm waters of the Gulf before impacting Texas.  Other computer models suggest that the storm might exit to the north, crossing Louisiana, Alabama or Mississippi.

Currently raking the western edge of Florida with heavy rains and high surf, Debby is a lopsided Tropical Storm, its center of circulation west of the rain bands.  This reflects the presence of upper level winds, crossing the storm from southwest to northeast and keeping the thunderstorms along its eastern and northern rim.  Should the storm remain in the Gulf and drift westward, it may escape this wind shear, allowing a closed system to develop (with thunderstorm bands circling the center of low pressure).  Such architecture is essential to the formation of hurricanes and it remains possible that this tropical storm could become Hurricane Debby in the western Gulf.  Time will tell but, for now, she has the forecasters baffled.

Saturday, June 23, 2012


There are few terranes that illustrate the science of plate tectonics and continental drift better than Avalonia.  This micro-continent formed as a volcanic island arc along a subduction zone off the African Coast; at that time, late in the Precambrian Era, Africa was attached to the other southern continents to form Gondwana, which stretched across the South Pole.  During the Cambrian Period, some 530 million years ago (MYA), as shelled marine life was exploding in diversity, Avalonia rifted from the African Plate and drifted northward ahead of the Rheic Ocean, which opened between it and Gondwana.

Late in the Ordovician Period, some 450 MYA, Avalonia docked with Baltica, the craton that now underlies Scandinavia, Eastern Europe and western Russia.  This combined continental mass then collided with Laurentia (proto-North America) during the Silurian Period (440 MYA) as plants and animals were first colonizing the land; the collision forced up the Northern Appalachians, an event known as the Acadian Orogeny.  When the Earth's land masses merged into Pangea during the Permian Period, about 270 MYA, Avalonia was caught in the middle, compressed between the northern and southern continents.

As the Tethys Sea opened east to west, some 200 MYA,  Avalonia remained with Laurasia (the combined northern continents).  During the Jurassic (150 MYA), the Atlantic Ocean began to open, splitting Avalonia as it divided the North American and Eurasian Plates.  Today, fragments of Avalonia form coastal New England, Nova Scotia and the Avalon Peninsula of Newfoundland on the North American Continent; across the Atlantic, it is represented by Wales, England and the northern portion of Western Europe.  Small fragments of Avalonia have also been identified in South Carolina and along the western rim of the Iberian Peninsula.

Friday, June 22, 2012

Australia's Great Basin

The Lake Eyre Basin of east-central Australia is a vast topographic bowl within which streams drain toward the lowest part of the basin, never reaching the sea.  Covering 440,000 square miles from southwestern Queensland to South Australia and from the southeastern corner of the Northern Territory to the northwestern edge of New South Wales, most of it is dry, desert landscape through which ephemeral streams lead to Lake Eyre, in the southwest corner of the Basin.  Nearly dry and coated with salt flats most of the time, the lake fills only twice each Century (on average); composed of a large northern basin connected to a smaller southern basin by the Goyder Channel, Lake Eyre covers 3700 square miles and has an average depth of less than 10 feet (when full)  The lowest point of the lake basin, in Belt Bay of the northern portion, is 50 feet below sea level while the rim of the lake is 30 feet below the level of the sea.

The Lake Eyre Basin began to form about 200 million years ago, when Australia was part of Gondwanaland.  Tectonic forces caused the crust of this region to subside and, within another 100 million years, an arm of the sea invaded the basin; when uplift occurred along the northern and eastern margins of the basin, the sea drained away and rivers flowed across the region, depositing sediments on their way to the ocean.  During the middle of the Pleistocene, about 1 million years ago, uplift along the southern rim closed off the basin and all streams fed Lake Diers, the much larger predecessor of Lake Eyre (as Lake Bonneville preceded the Great Salt Lake in the U.S.).  As the climate became warmer and drier late in the Pleistocene and into the Holocene, the flow through the rivers diminished and eventually became sporadic.  Today, what little water reaches the lake is via three primary river systems: the Georgina River from the north, the Diamantia River from the northeast and Cooper Creek from the east.  Most streams from the west and northwest dry up before reaching Lake Eyre.

During those rare periods when monsoon rains or tropical storms fill Lake Eyre, this remote oasis attracts huge flocks of shorebirds, terns and Australian Pelicans that nest on the islands and feed in the shallows; how these birds know that the distant lake is full remains a mystery.  Lake Eyre National Park stretches along the east shore of the northern lake, just a short 435 mile drive north from Adelaide.  Major towns within the Lake Eyre Basin include Alice Springs, Mt. Isa, Longreach and Broken Hill.

Thursday, June 21, 2012

Racing Past the Solstice

Last evening, the Northern Hemisphere crossed the summer solstice, its annual maximum tilt toward the sun.  Over the next six months, the sun will gradually retreat to the south and, in concert, our hours of sunlight will steadily diminish until we reach the winter solstice, on or about December 20.

It will take several weeks before we notice much change in the sunlight and several months before the longer nights take a toll on the summer heat.  Of course, the rate of change will be far more dramatic in the Arctic, sending shorebirds south by August and waterfowl in their wake.

Those of us who are not fond of hot, humid weather look forward to the cool, crisp weather of autumn and would like to accelerate the sun's retreat.  But it is the Earth's journey that governs our seasons, revolving around our home star on a tilted axis, steadily changing the angle of solar radiation that we receive.  Since we are already moving at 66,000 miles per hour to cover the 300 million miles between summer and winter solstices, a bit of patience seems to be in order.

Wednesday, June 20, 2012

Colorado's Beetles & Wildfires

After dealing with an overwhelming pine beetle blight for the past few years, Colorado residents now face what, so far, is a devastating fire season.  A modest winter snowpack, combined with a dry spring, has set the stage for lightening and human-induced forest fires.  In addition, the presence of so many dead pine trees will surely exacerbate that threat.

Our human-centric view of nature often leads to false conclusions about man's role in the occurrence of "natural disasters."  Many are quick to blame fire-suppression policies for both the beetle blight and the wildfires while others see the hand of God, a biblical punishment for the ills of human society .  But natural wildfires play a vital role in the maintenance of forest ecosystems, clearing out dead wood, opening the canopy and allowing the seeds of certain trees (lodgepole pines, for example) to germinate.  In like manner, pine bark beetles attack stressed or diseased trees and their massive infestations, which probably occur every century or so, restore forests with a diverse assembly of young, healthy trees.  While it is an unwelcome sight for residents and tourists, the remnant landscape of dead or burned trees is a necessary stage in the life of a forest; unfortunately, when viewed from the perspective of our brief human life span, it appears all too permanent.

Aspen trees, which spread by suckering and take advantage of clearings in the coniferous forests, will likely be the primary beneficiaries of these "disasters" in the short run.  Humans who chose to reside in western forests are among the primary victims, losing pristine scenery if not their homes.  Like those who live on barrier islands or along river floodplains, they were taking a chance; most will be philosophical, acknowledging the risk that comes with living in the Colorado mountains and respecting the natural forces that, over the centuries, mold our landscape.

Tuesday, June 19, 2012

The Congo River

Almost 3000 miles long and second only to the Amazon in its annual flow volume, the Congo River curves counterclockwise through the Democratic Repbulic of the Congo, taking in tributaries from a watershed that exceeds 1.5 million square miles.  The Upper Congo, known as the Lualaba River, receives the Luvua River from Lake Mweru, on the Zambian border, and flows northward, gathering the waters of other streams from Lake Tanganyika, to its east.  Alternately placid and turbulent, the Lualaba reaches Kisangani following a sixty mile course of rapids known as Boyoma Falls (formerly Stanley Falls).

From Kisangani to Kinshasa, at the west end of the Malebo Pool, the 1000 mile stretch of the Middle Congo is wide and navigable, receiving large tributaries such as the Lomami, from the south, the Aruwimi, from the east, and the Ubangi, from the northeast; just upstream from the calm, deep Malebo Pool, the Kasai River enters from the southeast.  Below Kinshasa, Livingston Falls, 90 miles of rapids and cataracts, make the Congo unpassable once again; to bypass this stretch, the Matadi-Kinshasa Railway was constructed in the 1890s.  From Matadi to the Atlantic Ocean, the river is broad and navigable and its braided delta begins just west of Boma; the Congo's total elevation drop, from Lake Mweru to this delta, is just over 3000 feet.

Crossing the equator twice and winding through the second largest tropical rainforest on our planet, the Congo evokes a sense of adventure, mystery and hidden danger.  Long before humans tainted its name with the atrocities of colonialism and slavery, this mighty river nourished and cleansed the Heart of Africa, connecting its lush savannas and dense forests to the distant sea; that role will surely continue long after we have plundered the natural bounty of our native Continent.

Monday, June 18, 2012

Missisquoi NWR

As heat and humidity grip much of the country over the next few months, those of us in the Midwest and Southeast will look for escapes to cooler, northern climes.  For naturalists, one option is a visit to Missisquoi National Wildlife Refuge, in northwest Vermont.

The Missisquoi River rises in the uplands of northeast Vermont, loops westward through southern Canada and then returns to Vermont to enter Lake Champlain along its northeastern shore.  There it has created a delta of marshlands, channels, mudflats and islets, providing ideal nesting and feeding grounds for migrant and resident waterfowl, shorebirds, waders, rails and wetland songbirds.  Established in 1943, the Missisquoi NWR now protects the delta, the adjacent Big Marsh Slough and parcels of northern forest.  At least 300 species of birds visit the refuge throughout the year and nesting species include ospreys, great blue herons, least bitterns, black terns, common goldeneyes, soras and Virginia rails, among many others.

Missisquoi NWR is located NNW of Swanton, Vermont, which is just west of I-89 (Exit 21).  Like most of our National Wildlife Refuges, it is accessible from dawn to dusk every day of the year; the refuge Visitor Center is open M-F and most Saturdays from mid May through October.  Adventurous visitors might want to rent a canoe in Swanton and explore the refuge marshlands from the cool waters of Lake Champlain.

Sunday, June 17, 2012

Glacial Lake Souris

Near the end of the Pleistocene, 10-15,000 years ago, large meltwater lakes formed along the retreating edge of the Continental Ice Sheet. One of these, Lake Souris, extended from north-central North Dakota into Manitoba, intermittently connecting with Glacial Lake Agassiz, to its east.

All of these lakes expanded and contracted depending upon their interconnections, the regional climate and the rate of meltwater production. Dammed by tongues of ice or moraines of glacial debris, some would occasionally break through their retaining wall, sending a torrent of water across the flat landscape of the Northern Plains. One such event involved Glacial Lake Regina of southern Saskatchewan, which flooded southeastward into Lake Souris; the broad, shallow channels of this flood remain evident today and are partly occupied by the Upper Souris River and its major tributary, the Des Lacs River.

East of Minot, the Souris River now enters the former lake bed of Glacial Lake Souris, following it north and gradually eastward to merge with the Assiniboine River of southern Manitoba; Lake Souris, itself, eventually drained into Lake Agassiz, which contracted into Lake Winnepeg after drainage opened to the north. National Wildlife Refuges now line the Des Lacs and Souris Rivers which, as we saw last summer, may still flood across the Pleistocene channels and lake beds when a deep winter snowpack is followed by heavy spring rains.

Saturday, June 16, 2012

The Flathead River

The Flathead River of northwest Montana rises via three primary forks. The North Fork heads in the mountains of southeast British Columbia and then flows south along the western edge of Glacier National Park. The Middle Fork rises in the Rocky Mountains, northwest of Great Falls, winding northwest and then westward to join the North Fork. The South Fork also rises in the Rockies, more directly west of Great Falls, and flows NNW, where it enters Hungry Horse Reservoir before merging with the combined North and Middle Forks. The primary channel of the Flathead River then enters the Rocky Mountain Trench, a broad valley formed by downwarping of the crust as mountains rose to its east and later occupied by Pleistocene glaciers. Flowing southwestward and then southward, the river passes Kalispell, Montana, and enters Flathead Lake; the Stillwater, Whitefish and Swan Rivers also feed the lake.

The largest natural freshwater lake (by area) in the western Lower 48, Flathead Lake initially formed from glacial meltwater behind a terminal moraine that was deposited late in the Pleistocene; the lake valley was also inundated by Glacial Lake Missoula as it expanded and retreated 30-15,000 years ago (see my blog on 4-2-12). Exiting the southwest corner of its lake, the Flathead River snakes southward across a landscape of plateaus and ridges before flowing westward through a rugged canyon to join the Clark Fork River.

The upper forks of the Flathead have all been designated National Wild & Scenic Rivers and are among the most remote and least disturbed streams in our country. Nevertheless, the North Fork faced possible contamination from proposed coal mining and gas production in southeastern British Columbia over the past few decades; fortunately, an agreement between the U.S. and Canada has, for now, blocked that "development."

Friday, June 15, 2012

Mt. Washington, NH

When I climbed Mt. Washington with a group of friends, in 1974, it was my first experience with mountain hiking. Standing atop the treeless summit, raked by a cold wind and looking out over the surrounding landscape of peaks and valleys, I enjoyed both a sense of accomplishment and the reward of magnificent vistas. We had ascended from Pinkham Notch, east of Mt. Washington, camping below Tuckerman Ravine for the night before a boulder-climbing assault on the summit the following day.

Anchoring the Presidential Range of northern New Hampshire's White Mountains, Mt. Washington tops out at 6288 feet, the highest summit in the northeastern U.S. The Presidential Range, trending southwest to northeast, catches both Canadian storm fronts and nor'easters from the Atlantic Seaboard, bringing copious precipitation to this high wall of Precambrian rock; Mt. Washington receives over 100 inches of precipitation each year, most of which arrives as snowfall (usually exceeding 300 inches). North and northeastward from Mt. Washington are, in sequence, Mt. Clay, Mt. Jefferson, Mt. Adams and Mt. Madison while, to its southwest, are Mounts Monroe, Franklin, Eisenhower, Pierce and Jackson. While the terrain climbs gradually across the western flank of the Range, Pleistocene glaciers carved steep cliffs and ravines along its eastern side; the Grand Gulf curves northeastward from Mt. Washington, Huntington Ravine drops across its eastern flank and Tuckerman Ravine forms a steep wall on its southeast edge.

The alpine summit and its Weather Observatory, which still holds the world record for a human-recorded surface wind speed of 231 mph in 1934 (eclipsed by an automated measurement of 253 mph from Cyclone Olivia, in Australia, 1996) can also be reached via a cog railway or via an auto road that winds up from Pinkham Notch. Whether visitors hike or ride to the summit, they are treated to spectacular mountain scenery and have a chance to observe a wide variety of Northwoods wildlife, including black bears, moose, white-tailed deer and a host of north country birds.

Thursday, June 14, 2012

High Deserts

To most of us, deserts are landscapes of dryness, sparse vegetation and perpetual heat. But, in high deserts, the interplay of elevation and dry air produces wide temperature variations from day to night and from one season to another. Examples within the U.S. include the Great Basin Desert, with floor elevations from 5000 to 6000 feet, the Red Desert of southern Wyoming, ranging from 6000 to 8500 feet, and the San Luis Valley of Colorado, with an average elevation of 7600 feet. In all of these deserts, hemmed in by mountain ranges, the annual total precipitation is below 10 inches and surface temperatures may vary by as much as 70-80 degrees F between night and day.

However, the high deserts of the U.S. pale in comparison to the extreme conditions found in other regions of our globe. The Gobi Desert of Mongolia and the varied Patagonian Desert of Argentina are somewhat comparable with regard to elevation but are far larger and are affected by the extreme conditions of neighboring ecosystems. The Atacama Desert of Peru and Chile, the driest on Earth, stretches from the sea to the foot of the Andes and thus harbors varied life zones from zero to 11,000 feet or more. Among the highest deserts in the Western Hemisphere are the Bolivian Salt Flats (12,000 feet) and the Salinas Grandes of Argentina, 12,500 feet above sea level.

But the most impressive high deserts on our planet are the Tibetan Plateau, north of the Himalayas, averaging 14,500 feet in elevation, and the Antarctic Plateau of east-central Antarctica, with a mean elevation of 9800 feet. Despite the fact that its ice and snow harbor over 70% of the fresh water on Earth, Antarctica is our driest Continent, with most of its precipitation falling along the coastal shelves; ascending toward the great plateau, the dry polar air cools further, dropping its meager cargo of moisture on lower terrain.

Wednesday, June 13, 2012

House Wren Mystery

Having spent a great deal of time in central Missouri over the past 15 years, I have become accustomed to the arrival of house wrens in late April, their loud song and buzzy chatter echoing through the neighborhood. By early summer, the parents are usually escorting their brood through the trees and shrubs, appeasing them with a smorgasbord of insects.

But this year, despite actively searching for these tiny songsters, I have not encountered a single house wren on our property and cannot recall seeing any on my walks to and from the University. I initially blamed their absence on landscaping activity in our backyard but that ended long ago and, still, no house wrens to brighten my evenings; frankly, I feel a bit betrayed. A few visits to our Colorado farm have turned up the usual number of house wrens along the Front Range, adding to the mystery here in Missouri.

Perhaps I am becoming less perceptive with advancing age or have been too busy this spring to give sufficient attention to our wild neighbors. I have even thought to blame the unusually warm spring and early leafing of our shade trees, which might have encouraged the wrens to move farther north before settling down. Then again, the populations of most other summer residents seem to be unaffected. This apparent dearth of house wrens may be just an illusion but, in some 40 years of birding, I can't recall anything quite so mystifying.

Tuesday, June 12, 2012

Siberian North America

Contrary to a popular assumption, the major tectonic plates of Planet Earth do not correspond directly to the contour of the continents and oceans for which they are named. The North American Plate, for example, extends westward from the mid-Atlantic Ridge, thereby including the western half of Iceland, the western half of the Atlantic Ocean, Greenland, Canada, the Continental U.S., Cuba, the Bahamas, the Gulf of Mexico, the northern Caribbean and the country of Mexico. Its western edge generally follows the west coast of Mexico, the U.S. and Canada (excluding the Baja and Southern California, which are on the Pacific Plate), curving westward below Alaska and its Aleutian Chain and then dipping southward to take in the northern islands of Japan; from there, the western edge of the North American Plate angles NNW, cutting across eastern Siberia.

The Chersky Range of eastern Siberia, trending NW to SE, is a swath of parallel ridges and deep gorges; geologically, these mountains represent a compression zone between the North American and Eurasian Plates and are thus prone to frequent earthquakes. Extending northwestward from the Chersky Range is the Laptev Sea Rift, cutting through the Laptev Shelf on the northern coast of Siberia; this rift is a continental extension of the Gakkel Ridge, the spreading zone of the Arctic Ocean which, across the globe, is continuous with the Mid-Atlantic Ridge. The North American and Eurasian Plates are thus diverging along the Mid-Atlantic/Gakkel Ridge and colliding at the Chersky Range.

Of more significance to politically-minded, nationalistic humans, eastern Siberia, including the Kamchatka Peninsula, is on the North American Plate while Southern California and Hawaii are on the Pacific Plate, tied tectonically to Tahiti, the Soloman Islands and Southern New Zealand. Perhaps, if we paid more attention to the geology of our planet and less to our cultural differences, we might be more devoted to our common welfare.

Monday, June 11, 2012

The Rise of Independence

A recent poll of Americans, reported on the PBS News Hour, revealed that 38% of us identify ourselves as being politically independent; some 32% expressed an affiliation with the Democratic Party while only 24% claimed to be Republicans. I suppose the other 6% are simply apathetic.

In light of ongoing stagnation within the U.S. Congress, it is no wonder that more Americans prefer to be identified as an Independent than to be associated with one of our traditional political parties. But one can hope that this move toward independence also reflects a broader degree of human enlightenment. While our species has a long history of tribalism, first adopted for self defense and later usurped to achieve and maintain power, this trait continues to be a source of discrimination, divisiveness and intolerance. In the spirit of John Lennon's immortal song, imagine a world without countries or religions.

Oppression, after all, has many faces. Its enforcement is not limited to dictators; rather, our freedom is often curtailed by the power of organized religions and entrenched political parties. The rise of independence will, over time, shatter their grip on the soul of humanity.

Saturday, June 9, 2012

Dry Rivers on the High Plains

Most of the rivers that cross the High Plains of the American West would hardly be recognized as creeks farther to the east. While the primary rivers that rise in the mountains, including the Missouri, Yellowstone, Platte and Arkansas Rivers deserve their title, many of the smaller rivers, heading on the High Plains Province itself, are dry for much of the year, transmitting water only after episodes of torrential rain or rapid snowmelt. Among these sandy channels are the upper tributaries of the Niobrara, Republican and Smokey Hill watersheds.

Cut off from Pacific moisture by the Continental Divide and located far from the Gulf of Mexico, the High Plains only receive copious precipitation when powerful storms draw in moisture laden air from the east, events that most often occur from February through June; indeed, this geophysical province receives less than 20 inches of precipitation each year. Yet, if we study the High Plains topography, we find that these meager conduits have managed to carve ridges, hills and valleys from the otherwise level plain, suggesting that they were more substantial streams in the past. In fact, during the Pleistocene Epoch (2 million to 10 thousand years ago) the regional climate was much cooler and wetter, giving rise to rivers that, in today's climate, have withered to channels of sand, prairie grass and scattered stands of cottonwood trees.

As with other ecosystems across our globe, it is impossible to understand the current geography without an appreciation for natural history and the region's underlying geology. In the case of the American High Plains, Pleistocene rivers sculpted the Tertiary deposits and underlying Cretaceous Sea sediments into the landscape that we find today; feeble and intermittent streams now occupy the valleys that those rivers left behind.

Friday, June 8, 2012

Rock Squirrels on the Piedmont

Rock squirrels have long been common residents of canyons throughout central and western Colorado and of the varied rock formations that rise along the base of the Front Range foothills. Our largest ground squirrel is easily recognized by his attractive salt-and-pepper coat and his large bushy tail. Most often seen lounging on rocks early or late in the day, these omnivores consume a wide variety of plant materials (nuts, fruits, vegetation) in addition to insects, carrion, bird eggs and even small mammals on occasion. Two litters are produced each year (mid spring and late summer) and, though they retire to their dens for most of the winter, they store food and are not true hibernators, becoming active during periods of mild weather.

Over the past few decades, rock squirrels have ventured onto the Colorado Piedmont and High Plains, following river channels from their original homeland in the foothills and lower mountains. Their expansion has been well documented along the Cache la Poudre River, in northern Colorado, and along the Arkansas River, from Pueblo all the way to the Kansas border. In all of my years hiking along the South Platte, I had not encountered rock squirrels until this week, when I saw a pair at the major rapids area in South Platte Park (just east of the golf course).

Though I am not familiar with scientific studies regarding their dispersal, I suspect that rock squirrels are spreading eastward due to both opportunism and human encroachment on their native habitat. Suburbs have increasingly pushed into the areas just west of the Dakota Hogback as well as along the primary canyons that incise the foothills. In addition, we humans have lined our river channels with rocky embankments, protecting our homes while producing new living quarters for the rock squirrels. Of course, over time, their presence becomes a nuisance as their digging and foraging creates havoc for human engineers and gardeners; once viewed as fascinating residents of our foothill parks, they are now despised as invasive varmints to be trapped or killed.

Thursday, June 7, 2012

Denver's Monster Storm

Late yesterday afternoon, a line of thunderstorms developed across northeastern Colorado, a typical occurrence in early summer. One of these was a tornadic monster that stretched from Castle Rock to the area just east of Denver International Airport.

While such storms usually move rapidly off to the east, this storm, unaffected by steering winds, sat in place throughout the evening, dropping torrential rain, producing large hail and spawning several tornados. In fact, by 10 PM, the massive thunderstorm began to drift southwest and then northwest, eventually stretching along the foothills west of Denver. Though radiation cooling generally causes Front Range storms to dissipate after sunset, this one continued to intensify and, by midnight, was illuminating the sky with incessant cloud-to-cloud and cloud-to-ground lightening.

Its final push across Metro Denver triggered severe thunderstorm and flash flood warnings from the National Weather Service. Here in Littleton, we received heavy rain and an inch or two of pea-sized hail; some areas reported golf ball sized hail and the region south and east of Denver, impacted twice by the same storm, received up to five inches of rain. Exiting the Front Range by 2 AM, the massive storm had put a significant dent in our drought and had produced the most spectacular light show that I have ever witnessed. Of course, for those impacted by large hail, flooding and tornados, the memories of this unusual weather event will be less positive.

Wednesday, June 6, 2012

A Morning Chat

On this bright, cool morning, we opted for a hike through the South Platte Valley, looping past several lakes that border the river channel. In one area, the trail crosses a brushy ridge with scattered groves of cottonwoods and it was there that I heard the unmistakable "song" of a yellow breasted chat, more like a loud, rambling conversation. Indeed, though classified as a warbler (our largest), the chat acts more like a thrasher or a catbird, skulking in the shrubbery and delivering its litany of seemingly unrelated calls and noises.

Solitary for most of the year, yellow breasted chats summer across the Lower 48, preferring riparian woods and brushy hillsides. Nests are placed in low shrubs and these common birds would probably go unnoticed were it not for the male's tendency to sing from an exposed perch, his bright yellow chest and abdomen glowing in the early summer sun. Here in Colorado, chats are especially common along streams of the lower foothills where they feast on insects and berries. While some winter along the East Coast of the U.S., most yellow breasted chats head to Mexico or Central America for the colder months.

This morning, our songster was accompanied by house wrens, lesser goldfinches, yellow warblers, song sparrows, black-billed magpies, broad-tailed hummingbirds, a Say's phoebe, northern flickers and those ubiquitous robins and house finches. Double-crested cormorants moved among the lakes, fishing for their breakfast, while great blue herons, a black-crowned night heron, flocks of Canada geese and squadrons of ducks passed overhead. But it was the chat that made our morning, delivering his strident lecture to all who cared to listen.

Tuesday, June 5, 2012

Front Range Drought

Following a lackluster snow season and spotty rain throughout the spring, Colorado's Front Range is tinder dry and wildfires have become a significant problem, especially for residents of foothill communities. Over the past two days, the fire risk has increased dramatically as hot, dry, southeast winds have raked the area; while the humidity has increased a bit with this upsloping wind flow, little precipitation has developed and "dry thunderstorms" threaten to ignite more fires.

Along the urban corridor, the winds are producing a welcome "wind-chill," making the mid afternoon heat feel less intense than it might on a calm day. A stroll along the South Platte revealed water levels lower than I have encountered in many years; with much of its flow diverted for irrigation and water supply, the shallow river attests to the ongoing drought in much of the State. On the positive side, the sluggish stream attracted a variety of birds from the parched fields and woodlands, including yellow warblers, belted kingfishers, spotted sandpipers, killdeer, swallows, great blue herons and mother ducks (mallards and wood ducks) with their broods in tow.

There is some hope that the gusty, upsloping winds will produce showers and thunderstorms overnight but, even if they do, a widespread, soaking rain is not expected. As often occurs along the Front Range, the precipitation will be spotty in nature, with some areas enjoying a cloudburst and others left in the windblown dust. In reality, a significant break from our ongoing drought will probably not occur until the late summer Monsoon pumps moisture up from the Desert Southwest. Let's hope that annual relief arrives early, rescuing the Front Range from what appears to be a destructive wildfire season.

Monday, June 4, 2012

High Plains Thunderstorms

Our trip from Missouri to Colorado today was almost entirely under sunny skies, with afternoon temperatures near 90 degrees F. The one, significant exception was an imposing wall of dark clouds, lightening and intense rain along the Kansas-Colorado border. Though our journey through the storms was brief and, thankfully, unaccompanied by large hail, the thunderstorms were training over Kit Carson County, including the city of Burlington, triggering a flash flood warning from the National Weather Service.

Encounters with severe weather can be unsettling in any location but they are especially terrifying on the Plains or on open water. In these areas, one gets both a broad view of the storm's size and ferocity and plenty of time to observe the approaching monster, wondering what it might do to your vehicle or boat. In addition, if caught in an open landscape, one experiences a sense of hopelessness, finding no means to escape the looming threat.

While some make their living chasing and photographing storms on the Great Plains, the rest of us are well advised to check weather forecasts prior to our journey and be willing to stop at a safe location if unexpected storms develop. Today's storms seemed to blow up before our eyes and we had no recourse but to slow down and hope for the best; fortunately, the major storms were well away from the highway as we passed through and we had only to contend with torrential rain and gusty wind. Once we were through this swath of fury, the clouds dispersed and we crossed dry, sun-drenched terrain all the way to Denver.

Sunday, June 3, 2012

American Creationists

This week, CNN reported on a recent survey of American adults that revealed almost half of us reject the concept of human evolution and believe that humans were created by God within the past 10,000 years; among Republicans, 60% hold this view. This large contingent of creationists is, to say the least, disturbing to those of us who accept the scientific method as the only legitimate means for solving the mysteries of the Universe and for defining our place within its vast realm.

The results of the survey suggest that two factors are at play. First, scientific education within the U.S. is woefully deficient, even among college-educated adults. Second, the influence of organized religion in America remains very powerful and, despite the copious scientific evidence that supports human evolution, many religious persons either choose to ignore that data or find the ancient, pre-scientific writings of early prophets more convincing. There is little doubt that religious beliefs, ingrained in childhood and sustained by fear and guilt, fuel distrust of science, as they have since the earliest days of human civilization.

The fact that we live on a small planet near the outer edge of a massive galaxy that is one of billions of galaxies in our Universe seems to have no bearing on their belief; neither does the evidence that the Universe is 13.7 billion years old, that Earth is 4.6 billion years old and that life has colonized our planet for 3.6 billion years. If the creationists are correct, God is a very patient deity indeed.

Saturday, June 2, 2012

The Birding Doldroms

For the amateur, summer is a good season to engage in birdwatching; a wide variety of species are present and the weather is conducive to both field study and patient observation. But, for veteran birders, June and July are probably the least interesting months of the year.

By June, the spring migration has ended and a population of well-known, frequently-observed summer residents has settled in our parks and neighborhoods. Early summer is an unlikely time to find rare vagrants, the cherished quarry of avid birders; rather, such wanderers are far more common in late summer, during the spring and fall migrations or throughout the lean months of winter.

Of course, travelling to other regions of the country or planet is the best cure for the birding blues, but, for many (if not most) of us, such a remedy is not feasible. Those who cannot travel must wait for shorebirds to start dribbling south in mid summer or be satisfied with visits by our less common summer residents. During these birding doldroms, I suggest that birders broaden their horizon, taking an interest in the wide variety of plants, insects, reptiles and other creatures that share our home ecosystem; by doing so, we also develop a better appreciation of the environment in which our resident and migrant birds obtain the essential elements of their survival.

Friday, June 1, 2012

A Breath of Spring

After weeks of summerlike heat, cool, Canadian air has dropped into the Heartland. The jet stream is ushering in this fresh breath of spring, dipping east of the Rockies, across the Southern Plains and then northeastward above the Mississippi and Ohio Valleys.

Here in mid Missouri, we awoke to clear, dry air and a temperature of 48 degrees F, twenty degrees cooler than recent overnight lows. Our high is forecast to peak near 70 degrees this afternoon, a pleasant change from the oppressive air that enveloped our region through most of May. Indeed, on this first calendar day of summer, we will enjoy our first spring-like day in many weeks.

Of course, nature pays no heed to the human calendar and her unpredictable style demands our attention. While we are grateful for her refreshing gift today, the next round of heat and humidity sits on our doorstep and a long, hot summer may soon take hold. Hopefully, she'll appease us with occasional waves of cool, northern air until the invigorating chill of autumn invades the Midwest.