GNFAC Avalanche Advisory for Mon Oct 23, 2017

Above average snowfall since mid-September has left 2-3 feet of snow on shady, high elevation slopes. Sunny aspects and lower elevations have little to no snow due to intermittent warm, sunny days (photo, photo, snowpit). Where there is enough snow to ride, there is enough snow to slide. Ice climbers, skiers, and hunters all need to prepare for avalanches this time of year.

Slopes where wind has drifted snow into thick slabs create the main avalanche concern. These wind slabs are more likely where the snowpack is deepest. This is also where skiing is most desirable due to smooth, rock free surfaces. Carefully assess the snowpack, and choose lower angle terrain if you’re unsure, or see clear signs of instability such as collapsing or cracking of the snow. On Saturday, climbers on the Sphinx found waist deep snow, then retreated to safer terrain when they witnessed cracking of 8” thick slabs. Terrain traps such as cliffs, trees, rocks, and gullies increase the consequences of even the smallest slide, and are more prevalent right now due to thin snow cover.

Hunters often travel solo and don’t carry avalanche rescue gear, so should completely avoid steep, snow covered avalanche terrain. Avoid deep, dense or hard drifts of snow near ridgelines and on the steep sides of gullies. If necessary, cross these features one at a time, at the top versus mid-slope, and watch each other from a safe area. Consider travel on slopes with shallow or no snow to minimize exposure to avalanches.

Ice climbers should completely avoid steep, high consequence terrain if it’s loaded with snow, and turn around at the first sign of instability such as cracking of deep drifts. A small, 15’ wide avalanche killed two climbers on the Sphinx in October 2004.

Skiers need to carry rescue gear as they normally would in the middle of winter (Beacon, Shovel, and Probe). Put fresh batteries in your beacon and practice using it, check your probe and shovel for damage, and check your partners’ gear before you leave the trailhead.

If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#GNFACobs).

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