AAC Publications - http://publications.americanalpineclub.org

Weather, Inadequate Protection—Tent vs. Snow Cave, Alaska, Mount McKinley

WEATHER, INADEQUATE PROTECTION—TENT VS. SNOW CAVE

Alaska, Mount McKinley

On July 13, 1989, at 0900, Rainier Mountaineering, Inc., guide Curt Hewitt (38) was blown from his camp near 5000 meters on the West Buttress of Mount McKinley while in his tent. Hewitt freed himself of the tent 180 meters down the slope. Although treated for hypothermia by his party, Hewitt did not sustain any injuries. The incident occurred midway through a 100 hour wind and snow storm. This is the second occupied North Face Pole Sleeve Oval to be blown off the West Buttress this season. (Source: James Litch, Mountaineering Ranger, Denali National Park)

Analysis

The tent was protected by snow walls a meter high. Hewitt and fellow guide John Craig (31) felt that these walls would sufficiently divert the wind over the tent. However, the tent had only three anchors in place: two ice axes and a picket were slipped through the floor loops. Only three guy lines were tied off, each to one of the floor anchors. Although the tent appeared to be protected from horizontal gusts, the three anchors were not sufficient to prevent a popping of the tent from wind gusting downward. One ice ax was pulled from the snow. The two other anchors remained in place, having failed at the attachment points of the tent.

Periods of high winds which may last for days are frequently experienced at all elevations on Mount McKinley. The use of particularly wind-exposed sites lacking existing natural protection, such as the West Buttress above 4800 meters, leave climbers with few options, especially larger parties. Snow walls completely surrounding the site that exceed the height of the tent, as well as anchors positioned at all possible tie down points, are essential precautions. Wind blasts forcing the tent in any direction (including upward) should be anticipated. Low-profile tents with numerous tie-down points, and a sufficient number of anchors carried by the party must be considered beforehand. If one must utilize particularly wind-exposed sites, snow caves are an additional consideration.

It is interesting to note that the Pole Sleeve Oval in this incident did not collapse or snap poles, despite the tumbling fall of 180 meters. Hewitt felt strongly that he could have held the fall at the first soft snow patch had the tent collapsed rather than act as a sail. (Source: James Litch, Mountaineering Ranger, Denali National Park)