In November 2007, a man died after climbing Cathedral Peak in Yosemite with his partner. They expected to return the same day but were trapped on the descent when it began to snow, and one climber succumbed to hypothermia. In June 2008, a man died on Rainier after a freak blizzard caught three unsuspecting hikers in a storm that dropped 2 feet of snow. They had only left Camp Muir on a day hike. Although two of the three were experienced climbers and had previously reached the summit of Rainier. However, they didn’t have the 10 essentials, including emergency shelter, and the fallen hiker gave his life by providing his body as insulation from the snow. They all suffered from hypothermia and frostbite.
http://www.sierrajournal.com/2010/01/06/importance-of-mad-snowcamping-skillz-in-the-sierras/