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3 IntroductIon: ArrIvAlInAvAlAnchEcountry d r. charlES fox gardinEr found hiS firSt day in thE mountains fundamentally strange. A self-described “tenderfoot,” Gardiner arrived in Crested Butte, Colorado, in the 1880s. As he walked toward his hotel, the towering mountains, deep snow, thin air, and residents skiing about made an immediate impression. Then he “heard a distant rumble that sounded like thunder in the mountains; it grew heavier, the walk under . . . [his] . . . feet shook, and then, with a last roar, the sound stopped.” He remembered, “No one on the walk seemed to notice it so I asked a passing miner” what had happened. The miner replied, “‘Why, man alive . . . don’t you know snowslides when you hear them?’” This first encounter with the “growl of the mountain giant that strikes terror to those . . . in its path” reinforced for Gardiner the fact that he had come to a place quite different from the home he had left in New York.1 Over the years Gardiner spent in the Elkhorn Range, he would become better acquainted with avalanches, or snowslides—as the miners called them—and make many adjustments to practice medicine in his new home. He would learn to ski, which was the only way to reach patients in the wintertime, and to treat maladies like snow blindness—temporary loss of sight caused by the sun’s reflection off the snow. And like others before and after him, he would discover that the process of community building in a mountainous environment demanded he cope with extremes of climate and topography. Gardiner had arrived in what is known today as Avalanche Country, places where steep slopes and snow converge with deadly potential. The conditions that lead to avalanches begin with snowflake structure . Snowflakes form many shapes—the more complex the shape, the more tightly the ice crystals bond together on the ground. Temperature, 4 § introduction moisture content, wind speed, and melting and refreezing rate also affect bonding. Snow falls; layers build. Avalanches occur most often on slopes between 30 to 60 degrees, when the weight of new snow breaks the bonds between the underlying layers. Two of the most common types of avalanches are loose snow and slab avalanches. A loose snow avalanche begins at a single point at the top of a ridge and as it streaks downhill it destabilizes the surface snow in its path, which then becomes part of the slide. This kind of slide often follows creek beds or gullies and tends to recur, following the same path year after year. Slab avalanches begin when a crack, perpendicular to the fall line, forms between snow layers. The mass of unstable snow breaks off along the crack and moves downhill; slab avalanches can comprise huge amounts of snow, move up to 200 miles per hour, and are less predictable than loose snow slides. Several factors make regions within the Mountain West particularly prone to avalanche activity. In southwestern Colorado, for example, the San Juan Mountains are extraordinarily steep and receive a fair amount of sun in the wintertime. This creates particularly hazardous snow conditions , because the sun melts both surface and subsurface layers of snow, which then refreeze at night. This cycle produces unstable snow layers with poor cohesion. As a result, the snow cover of the San Juan region has an extremely unstable stratigraphy, which means that the layers are more likely to slip off one another on steep slopes, creating an avalanche.2 The Cascades in Washington also experience frequent slides. They are also steep, but receive massive amounts of wet, heavy snow—averaging nearly thirty-eight feet during the winter. Changes in the rate of snowfall, temperature fluctuations that mean it can rain and snow during the same storm, alterations in wind speed, and variations in the density of the snowpack contribute to conditions that increase the likelihood of slides.3 Those with avalanche experience argue that where slides have fallen once, they are likely to occur again. This belief influences modern avalanche -control methods on highways and at ski resorts where artillery and dynamite are used to stimulate slides before catastrophic amounts of snow have accumulated. Over time, avalanche science has become a respected field of study; manuals advise backcountry users how to avoid risk; and technological advances like avalanche radio beacons, a device worn by skiers that emits a tracking signal, improve chances of survival for victims buried in slides. Nevertheless, deadly disasters occur every year. The num- [3.144.96.159] Project MUSE (2024...

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