Utah's Powder Keg

Famous for deep powder that attracts skiers from across the globe, the Wasatch Front of Utah is about to unleash its bounty on those who live along its base. Thanks to a persistent atmospheric trough that produced a chilly, wet spring, the snowpack is near record levels and has barely begun to melt, a process that generally peaks in May. When summer heat suddenly arrives, a torrent of meltwater will sweep through the steep canyons of that majestic range, inundating the towns and cities that lie in its path.

Unlike in other areas of the country, the rivers that drop into the Great Basin soon spread across the flat terrain, forming broad, shallow lakes that evaporate in the intense sun of the high desert. Of course, Salt Lake City and other urban centers now occupy that basin and, when reservoirs are unable to contain the flow, flooding results. In light of the deep snowpack and delayed melting cycle, such a scenario appears to be unavoidable.

The bounty of mountain snow is vital to the ecosystems of the Western U.S., sustaining forests and producing corridors of vegetation across the semiarid landscape that lies below; without it, humans could not have colonized the region. But nature is fickle, bringing drought one year and floods the next; we must understand the risks that come with her varied landscapes and learn to live with her changing moods.

Prickly Pear Cacti

Prickly pears, members of the genus Opuntia, are the most widespread and heavily utilized cacti on our planet. Native to the Americas, more than 200 species now grace the globe, many of which are under cultivation for food, livestock feed and a variety of materials.

While most species of prickly pear colonize desert or semiarid life zones, they are found from southern Canada to South America and are the only cacti native to the eastern U.S. Characterized by fleshy pads (nopales) which harbor long, fixed spines and small, fine, barbed glochids, most prickly pears grow in dense clusters, low to the ground; however, some species branch upward to form shrubs or small trees, reaching heights of seven feet or more. Prickly pear flowers, which bloom from April to June (depending on latitude) are most often yellow or orange but may be red, pink or purple in color. Their globular fruit, also coated with glochids, is consumed by birds, rodents, deer, peccaries and other wildife and have been used by human communities to make candies, jellies, juices and coloncha (an alcoholic beverage); the nopales are also edible, mixed into salads or cultivated for livestock.

Vigorous, hardy and fast growing, prickly pears have been used for natural fencing and, in areas without natural predators, have become a threat to native flora. Various parts of these cacti have provided dyes, medications, fiber and a sticky resin, used to make plaster; most recently, prickly pears are being investigated as a potential source for biofuel. Attractive and prolific, prickly pear cacti brighten the landscape while offering many additional gifts to humans and wildlife alike.

The Desert Owl

Elf owls, the smallest owls in North America, are summer residents of the Sonoran Desert in southern Arizona; some inhabit the Chihuahuan Desert of southernmost New Mexico while others breed in dry country along the Rio Grande River of southern Texas. Less than six inches tall, these tiny raptors are best identified by their yellow eyes, white eyebrows and round, tuftless head.

Calling from a potential nest cavity in April, the male attracts his mate and both parents incubate the eggs (usually 2-4) for several weeks. Nest cavities, always more than ten feet from the ground, are abandoned woodpecker holes in saguaro cacti or in sycamores along streams near the base of mountain ranges; gila woodpeckers usually sculpt the saguaro cavities while flickers and acorn woodpeckers provide those in riparian areas. Strictly nocturnal, elf owls feed primarily on flying insects but may grab a scorpion or ground beetle; during the breeding season, they are often active at dusk but are otherwise best observed within their cavity during the daylight hours.

Relying on a diet of insects, these small owls migrate southward into Mexico for the winter, when chilly nights eliminate their prey in the Desert Southwest. Since they inhabit arid landscape with few larger owls, roost in cavities far from the ground and capture their meals in mid-air, elf owls have few natural predators and may live up to six years in the wild.

Carrabassett Flashbacks

In 1981, after a hot, humid summer in Arkansas, I flew to Maine to look at a practice opportunity. The town was rather small but the medical community was welcoming and, of course, the prospect of living amidst the rugged mountains, glacial lakes, deep woods and spectacular seascapes of that State was surely appealing.

During my visit, one of the older physicians, sensing my enthusiasm for the local geography, took me for a drive up the Carrabassett River Valley, through the fragrant Northwoods, studded with ponds and bogs. The air was cool, mountains loomed in the distance and signs warning of wayward moose were spaced along the roadway. In contrast to the sluggish, muddy streams of the Deep South, the clear, chilly waters of the Carrabassett rushed above gravel beds and splashed among ancient boulders, dropped by the Pleistocene ice sheets.

For a variety of reasons, we declined the opportunity in Maine and ended up in the dry, sunny climate of the Front Range. Though I have no regrets, I often recall that drive along the Carrabassett River, especially when summer heat saps my enthusiasm for outdoor adventure. Over the past week, those flashbacks have come in steady waves.

Madera Canyon

The mountain ranges of southeast Arizona offer steppingstones of forest for birds migrating between the Sierra Madres of Mexico and the Rocky Mountains of western North America. In addition, these sky islands provide cool, moist retreats for the birds and other wildife that reside in the Sonoran Desert, concentrating their populations and making them more accessible to humans who hope to observe them. Harboring a mix of Mexican and North American species, these ranges are thus renowned as superb birdwatching sites and Madera Canyon is among the more popular destinations.

Incising the northwest flank of the Santa Rita Mountains, 25 miles SSE of Tucson, Madera Creek rises along the crest of the range (an elevation of almost 9500 feet) and drops 7000 feet to the floor of the desert. Within its spectacular canyon, varied life zones attract a tremendous diversity of plant and animal life, including more than 200 species of resident and migrant birds. Among the more treasured sightings are elegant trogons, sulfur-bellied flycatchers, painted redstarts, yellow-eyed juncos, flame-colored tanagers, whiskered screech owls and 15 species of hummingbirds; the latter are best observed at feeding stations around the Santa Rita Lodge. Other canyon residents include black bears, mountain lions, bobcats, coati, ring-tailed cats, wild turkeys, black-necked garter snakes, tiger rattlesnakes and canyon tree frogs.

Accessed by a central roadway and numerous trails, Madera Canyon is a popular site for hiking and camping throughout the year; day use and camping fees are charged. Madera Creek, which sculpted this magnificent canyon, generally flows from the monsoon season of mid-late summer until depletion of the snow pack in early spring but can be dry for months at a time. Birders are advised to avoid the weekend crowds and to visit the Canyon early or late in the day.

The Nature of Wildfire

The massive wildfire that is ravaging northeast Arizona is surely causing hardship for many humans and its scar will stretch across the landscape for many years to come. But wildfires, like floods, hurricanes and other weather-related "disasters" have been essential to the health of natural ecosystems throughout the history of our planet.

Usually triggered by lightening and fueled by drought, wildfires serve to clean out our forests, recycle nutrients and protect our prairies. For many plants, as with lodgepole pines, wildfire is an essential factor in the reproductive cycle, releasing seeds and setting the stage for germination. Furthermore, fire removes invading, alien plants that are unable to withstand its effects, clearing the landscape for native species.

While a large number of creatures may succumb to wildfire, most animals that live in fire-prone ecosystems adapt to these seasonal events, escaping the flames within burrows or using their natural skills to flee the torrent. Humans, on the other hand, tied to their plot of earth, are at the mercy of wildfires and often lose their homes and possessions; the choice to live amidst the natural beauty of fire-born ecosystems comes with a price.

Fence Lizards

Fence lizards are the most common and widespread lizards in the eastern and central U.S. The northern fence lizard ranges from the Mid-Atlantic region to the edge of the Great Plains and is especially abundant in the wooded hills of the Appalachian and Ozark Plateaus; the southern subspecies inhabits the pine woodlands of the Coastal Plain, from the Carolinas to Texas.

Named for their habit of basking on fence posts, these lizards spend much of the day in trees, chasing down insects, spiders, caterpillars and other invertebrates. Hikers often encounter them as they sprint across trails or scurry through the leaf litter but these agile reptiles usually escape to the safety of a tree, hiding on the opposite side of the trunk.

While both sexes are drab colored, with gray-brown scales, males sport patches of blue on their throat and sides during the breeding season. Mating occurs soon after hibernation and up to 15 eggs are laid by late spring, hatching in late summer or early autumn. Miniature replicas of the adults, young fence lizards are vulnerable to a wide range of predators, including birds, shrews, opossums and raccoons.

The Brilliant Wader

Natives of tropical South America, Central America, the Caribbean, South Florida and the Texas-Louisiana Gulf Coast, roseate spoonbills are distinctive waders that are sought by birders and photographers alike. They favor shallow, coastal bays where they feed on small fish and marine invertebrates, grasping prey with their sensitive, paddle-shaped bills. Due to their bright pink plumage and long, reddish legs, roseate spoonbills are often mistaken for flamingos; in fact, they are closely related to ibis and, like their cousins, fly in linear squadrons with necks outstretched.

Roseate spoonbills nest in mangroves or on offshore islands with low vegetation, often in large, mixed colonies that include herons, egrets, ibis, cormorants and pelicans; 1-4 eggs are incubated by both parents and the young will fledge within two months of hatching. Juvenile spoonbills often wander farther north in summer, appearing along the upper Gulf Coast and, occasionally, in the lower Mississippi Valley.

Threatened by both plumage hunters and the use of DDT in the early 20th Century, roseate spoonbills have since made a comeback; however, they, like other waders, now face habitat loss due to coastal development, pollution and the drainage of wetlands. On the other hand, these once rare birds have become quite common in some areas, turning up along golf course ponds and other man-made waterways.

Hazy, Hot & Humid

After a cool, wet spring, we have gone directly from April to July here in central Missouri. That dreaded summer forecast for hazy, hot and humid weather is blaring from the TV and we expect highs in the nineties (F) for most of the coming week.

The heat has driven the periodical cicadas into a frenzy and, by mid afternoon, they are everywhere, zooming through the air, buzzing from the trees and covering every exposed structure. Due to chilly, wet weather through much of May, they are two weeks behind schedule and should plague our area well into June. While their noisy din is annoying for humans, their massive numbers provide a bonanza of nutrition for birds and other predators and one can only begin to imagine the wealth of nutrients that their decomposing bodies return to the soil and plants.

Never a fan of hot, humid weather, I am already looking forward to the invigorating air of fall; more than two weeks before the summer solstice, it's not a good sign that heat advisories blanket much of the country. We can only hope that cool, Canadian fronts provide frequent respites over the next several months; otherwise, this season of heat and humidity will be especially long and oppressive.

Hominids & the Sahara Desert

The vast Sahara Desert, which stretches across North Africa, began to form in the late Miocene and early Pliocene, some 10 million years ago (MYA). South of this geophysical region, gorillas diverged from the hominid line about 9 MYA and chimpanzees followed 7 MYA. By 4.5 MYA, Australopithecus appeared in the Rift Valley of East Africa and, by 2 MYA, Homo erectus had evolved.

While the Sahara may have been a natural blockade to the northward migration of the earliest hominids, the Pleistocene Epoch (2 MYA to 10,000 YA) brought wide swings in the global climate, marked by four periods of glaciation. During these glacial periods, a cool, wet climate caused the Sahara to contract, opening corridors of savannah that likely permitted ancestral hominids to migrate northward, into Eurasia. Following earlier migrations of Homo erectus, Neandertals began to leave Africa about the time that humans were first appearing, some 150,000 years ago, and occupied Europe by 100,000 years ago. Man remained in sub-Saharan Africa until about 60,000 years ago, when the Wisconsin glaciation permitted migration through northeastern Africa and, due to lowered sea levels, directly across the Red Sea to the Arabian Peninsula.

Nomadic human tribes likely entered parts of the Sahara Desert from the earliest days or our existence but extensive exploration and settlement of that harsh landscape would not occur until the Holocene, aided by the domestication of goats (10,000 YA), sheep (9000 YA), cattle (8000 YA) and dromedary camels (4000 YA). Even today, most human settlements lie in fringe regions of the Sahara and interior towns are limited to natural oases, the Nile Valley and volcanic highlands.

Exploiting Human Nature

As a physician, I regularly witness the less attractive features of human nature but it has been the explosion of cable channels and social networking that has fully exposed, if not celebrated, our obsession with power, sex, celebrity, death and various forms of human turmoil.

Though religious and political scandals, corporate greed, domestic violence and civil rights abuses have occurred throughout history, modern technology assures that we are constantly exposed to these dark human traits. While it is important to stay informed about the ills of society and while the exposure of such activity is essential to its eradication, a wide variety of cable channels feed on dysfunctional human behavior, turning human tragedy into a lucrative form of entertainment.

Even more disturbing, the rise of social networking, encouraged throughout society, feeds this exhibitionism, offering immediate fame to those who take advantage of our dark obsessions. As individuals, we have little control over this cultural trend but, alarmed by its effects, one can certainly choose not to participate in the feeding frenzy.

New England Tornadoes

While we usually associate tornadoes with the Great Plains and Southeast, as we observed yesterday, they can occur in any region of the lower 48 States. Coming on the heels of tragic storms in Missouri and Alabama, the deadly tornadoes in Massachusetts seemed to suggest a doomsday scenario but their occurrence was merely a reflection of the typical weather patterns that produce such storms.

For the past few days, a dome of hot, humid air dominated the eastern U.S., from the Gulf of Mexico to New England; this atmospheric ridge was the product of an active, late spring jet stream, which dipped through the West and then looped northward across the Great Lakes and southern New England. To its north, Canadian high pressure was dropping southward, producing a clash zone across Massachusetts that was further energized by the turbulent jet stream. As typically occurs, severe thunderstorms ignited when the cold air undercut the hot, humid air and intersecting winds(the westerly jet and strong, southerly surface winds) produced rotation within these storms, spawning the deadly tornadoes.

When tornadic storms sweep across the vast plains, destroying barns and uprooting trees, we pay little attention to their power. Unfortunately, we have witnessed a series of direct hits on urban centers, raising our awareness of their destructive force and leading to the false assumption that a major change has occurred in our planet's atmosphere. Once again, our brief life spans and the relatively short period of recorded weather history produce this false conclusion and will lead some to blame these tragic events on global warming or divine intervention.

Common Snappers

Though widespread across North America, from the foot of the Rockies to the Atlantic Seaboard and from southern Canada to the Gulf Coast, common snapping turtles favor the muddy bottom of shallow lakes, ponds and rivers and are not often encountered by the casual naturalist. When seen, they are usually lumbering across country roads, searching for nest sites or new feeding grounds.

Despite their reputation as vicious predators, snapping turtles are opportunistic omnivores, feeding on a wide variety of plant and animal life, including carrion; while they will snare an occasional duckling or young muskrat, they are more likely to dine on decaying carp, aquatic vegetation, frogs, water snakes and smaller turtles. Mating is also opportunistic, occuring from mid spring to late autumn; since females can store viable sperm for years, one encounter is sufficient to fertilize several clutches of eggs. Up to ninety eggs are deposited in a pit, dug by the female in late spring, and will hatch in 2 to 4 months, depending upon the soil temperature; in northern latitudes, the young may not emerge until the following summer.

Hunted by humans for their meat, common snapping turtles cannot fully retract their head, legs and large, armored tail and are thus vulnerable to other predators when out of water; in southern lakes and streams, they may also become victims of alligators. Weighing up to 60 pounds and sporting a shell up to 20 inches in length, snappers may live for 30 years in their natural habitat of freshwater or brackish wetlands.

A Ridge of Summer

A northward shift of the jet stream has allowed a ridge of summer heat to invade the central and eastern U.S. over the past 24 hours and is expected to remain in place for Memorial Day. Blocking the invasion of Pacific fronts, this dome of high pressure is shunting storms along its outer rim and, at least for the Holiday weekend, the soggy and storm-ravaged Midwest will be spared another round of severe weather.

Ushering in the first major wave of summer, this atmospheric ridge should help to dry out the muddy fields that stretch across the till plains and, for now, will reduce flow into our swollen rivers and streams. As expected, the heat has energized the periodical cicadas here in Missouri and the sunny weather, arriving just in time for the traditional kickoff to summer, is especially welcome after a cool, rainy spring.

Of course, this respite will be brief. A deep trough across the West, bringing snow as far south as northern Arizona, will nudge eastward as the ridge begins to collapse; in concert, the storm-laden clash zone will also shift to the east and, fueled by the summer heat, severe weather will erupt across the Heartland. It will be July before the jet stream settles across Canada; until then, its gyrations will plague the lower 48 and destructive storms will continue to grab the headlines.

On the Safe Side

After raking the Plains, Midwest and Mississippi Valley with severe thunderstorms, deadly tornadoes and torrential rains for the past week, the potent storm system moved east of Missouri overnight and we are now on its safe side. While it will still unleash severe weather from the Gulf Coast to New England today, the system is expected to weaken significantly over the coming weekend.

Here in Missouri, wrap around showers and a north wind will produce a raw, chilly day but the threat of dangerous thunderstorms has passed, at least for now. As the storm system moves further to the east, heat and clearing skies will build in from the southwest, drying the soggy landscape but setting us up for the next round of spring storms when another Pacific front drops from the Rockies.

It has, indeed, been a cool, wet spring in the Heartland as the jet stream has guided storms across the Northern and Central Plains. While their trailing cold fronts have dipped into Oklahoma and North Texas, the drought persists across most of the Lone Star State; relief for that area will likely come in the form of tropical storms and the summer monsoon, still a month or more away.

A Delayed Chorus

In light of an exceptionally large brood in 1998, this spring's emergence of 13-year periodical cicadas in central Missouri was forecast to be overwhelming. However, it appears that the excessive rain and cool temperatures have, at the very least, delayed the spectacle.

Unlike the annual dog-day cicadas, periodical cicadas emerge in massive numbers every 13 or 17 years. Following a prolonged stage as nymphs beneath the soil, they climb onto a tree or other structure and molt to the adult phase, which lasts only a month or so. As adults, these cicadas are focused purely on producing the next generation; the scratchy calls of the males create a deafening chorus from dawn to dusk which increases in concert with the daily temperature. Once mating has occurred, the female lays her eggs in furrows along the tender stems of shrubs and trees, causing significant damage when the cicada broods are massive. If not eaten by birds, the eggs hatch and the nymphs drop to the ground where they burrow beneath the soil and attach themselves to a root for the next 13 or 17 years.

In the Midwest, periodical cicadas generally emerge by mid May and their noisy, adult population peaks by the end of the month before fading away in June. From an evolutionary point of view, it appears that these mass breeding cycles serve to overwhelm predators (crows, jays, raccoons, opossums, house cats etc.), thereby ensuring that their next generation is safely emplaced. As we move into a hot, dry spell next week, we'll likely experience the full impact of the cicada invasion.

The End is Near

After wrongly predicting that human life would end this past weekend, an evangelical preacher has become the target of jokes by comedians and newsmen alike. But, from the perspective of natural history, his guess may not have been too far from the truth.

Some 13.7 billion years after the Big Bang and 4.6 billion years after the formation of our home planet, the human race is less than 150,000 years old but already facing our own extinction. The end will not likely come by time zone, as the preacher suggested, but it could unfold rather rapidly, the consequence of a major asteroid strike or supervolcano eruption. More likely, we will orchestrate our own demise, continuing to ravage the environment through excessive consumption, pollution and unbridled population growth.

While the preacher's forecast was delusional, based on religious conviction and self-importance, the assumption that man can continue to plunder the natural environment without consequence is equally short-sighted. We may have no control over asteroids and supervolcanoes but we can eliminate human behaviour that will lead to our own, untimely extinction.

The Noise Industry

As a naturalist, I enjoy walking on the beach to the sound of crashing surf and frantic gulls. I relish tranquil bays, cathedral forests, the solitude of deserts and the quiet inspiration of mountain vistas. Unfortunately, there is a growing industry that often deprives us of such experiences.

Marketed as exciting ways to explore nature, jet skies, four-wheelers, dirt bikes and snowmobiles have invaded the landscape, polluting the environment with their noise and fumes. While essential vehicles for certain cultures and businesses, they have spawned a population of "nature lovers" who are more interested in speed and power than in the natural surroundings through which they race. Those of us who do not share their infatuation with combustion engines must, unfortunately, accept the side effects of their activity. National and State Parks, after all, are for the people, not so much for the environment.

Many who read this blog will perceive my views as just more selfish gibberish from a tree-hugging purist. I gladly accept that title if, in some small way, it would lead to more restrictions on the use of motorized noisemakers in nature preserves and wilderness areas.

A Parade of Supercells

Heading east in central Kansas last evening, I witnessed a parade of supercells, spaced across the eastern horizon; each half-again as tall as Mt. Everest, they reflected the setting sun. As I grew closer to this spectacle, the gaps began to close with new thunderstorms as outflow from the parent cells created lift. Soon, a massive wall of chaos loomed across my path; fortunately, I had made plans to spend the night west of the storms.

Safely in my motel room, I tuned into the Weather Channel and found that an interrupted line of severe thunderstorms, some with tornadoes, stretched from East Texas to Minnesota. I was also entertained by two of the Channel's expert stuntmen, doing exactly what they tell us not to do: standing in the dark near intense storms, looking for tornadoes with the aid of limited radar and night-vision glasses. Fortunately, no on-air mishaps.

The culprit for the severe weather was a massive, upper level low, parked over the Northern Plains. Still in place today, it will spawn new waves of storms as dry air from the west is swept into humid air moving up from the Gulf. Indeed, as I approached eastern Kansas this morning, puffy clouds were lining up above the hazy surface air, ready to ignite severe storms as afternoon heating intensifies. And don't worry, those courageous storm chasers are still in the path of the storms, ready to bring us live scenes of destruction.