It's late in the day, getting cold. Your legs are tired. Your feet hurt. Long shadows fill the bowls and moguls of the ski slope, places where the snow has turned icy. You're about ready to quit, but the crowds are thinning out and you decide to make one last run down the big hill.
That is the point of maximum risk, a time when your odds of being killed or seriously injured are perhaps four times as great as on that first powdery run in the morning, according to ski safety researchers.
The skiing deaths of two nationally known figures--Sonny Bono and Michael Kennedy--in the span of a week certainly qualify as a fluke in a sport that is, statistically, seven times safer than traveling by car. But Bono, who smashed into a tree Monday in South Lake Tahoe, and Kennedy, who hit a tree on New Year's Eve in Aspen, Colo., both died very late in the afternoon, when fatigue, ice and poor visibility pose a triple threat even to accomplished skiers--as both were.
Bono was killed about 4:30 p.m., Kennedy about 4:15, each on a slope rated for intermediate skiers. At many resorts, chair lifts stop operating by 4 o'clock, when mountain shadows coat vast swaths of snow in an icy glaze.
"The injury rate goes up significantly by that time of day," said Larry Young, a professor at the Massachusetts Institute of Technology, who conducted one of the landmark studies of ski accidents at a resort in New Hampshire.
Young's research, more than a decade ago, found that serious injuries peaked about 3 p.m., well after the day's crowds began to dwindle. The risks grow even greater as evening approaches, but the actual number of injuries begins to drop as more skiers seek out warmer indoor activities at pubs and restaurants.
The typical ski injury happens after three hours on the slopes, Young said. A Swedish scholar, Ejnar Eriksson, also noted that accident rates spike upward on the third day of a ski holiday, when leg muscles have gone through enough dips and turns to leave them rubbery and weak. Eriksson, who took muscle biopsies from volunteers, discovered that they had almost completely depleted their reserves of glycogen, the starchy substance that the body converts to sugar as a fuel source.
"By the third day," Young said, "they no longer had much action left in their fast-twitch fibers, the parts of muscles that you use in sudden movements, like jumping."
Bono, 62, had been skiing at Lake Tahoe since Dec. 26 and was killed while traveling through a heavily wooded section of mountainside. A photographer working at the Heavenly Ski Resort, where Bono died, told the Associated Press that Bono ignored posted warning signs prohibiting skiers from zigzagging among trees.
"There are signs all over this mountain saying, 'No tree skiing,' " said the photographer, who asked not to be identified.
Kennedy, 39, hit a tree while engaged in a high-speed game of downhill football, played with a water bottle during the last run of the day. A day earlier he had been playing the same game, drawing concern from resort officials who asked his mother, Ethel, to persuade him to stop, according to a report in Time magazine.
Details of the two accidents remain sketchy, leaving some experts reluctant to speculate about why they occurred. It remains unclear, for example, whether Bono suffered any kind of equipment failure or medical problem, such as a stroke or heart attack.
No one was skiing with him at the time the congressman and former pop singer crashed.
Even so, the two deaths--especially Kennedy's--were very typical of the pattern in ski deaths. Almost invariably, skiers who die are men, not women; they ski very well; and they are killed on intermediate slopes while traveling at high speed. Most of the time, they hit a tree.
Jasper E. Shealy, a scholar at the Rochester Institute of Technology in New York, describes it as "testosterone poisoning," the extraordinary tendency of many young males to take great risks. Except for his age, Bono may have belonged to the same group: men from their late teens to mid-30s who like to push the limits of their abilities. Relatively young, risk-taking men also account for an overwhelming number of mountaineering accidents, boating accidents, skydiving deaths and single-car auto fatalities, said Shealy, who has studied ski accidents for more than 26 years.
"It's not unique to skiing," Shealy said. "Males are the risk-takers, and one of the consequences of taking risks is that sometimes you lose.
"You generally find the fatal accidents occurring to the more experienced [skiers], not to the less experienced," he added.
Although rank novices tend to crash more often, they are usually traveling too slowly to get badly hurt. It often takes a certain amount of expertise to venture into dangerous territory.