Hatcher Pass

The avalanche danger is MODERATE for WIND SLABS avalanches at upper elevations above 3,500'. The danger is LOW elsewhere. You are most likely to trigger a slide where active winds have built fresh drifts of snow. This problem most likely exists at upper elevations near ridgelines, to the sides of gullies, or along convex rolls. Watch for freshly formed pillows of drifted snow, a wind-textured snow surface, or freshly formed cornices, as these are clues that you have found a wind-loaded slope. Spot your partners and travel one at a time on suspect slopes. 

Last week saw settled weather, with a skiff of snow over the weekend and trace to 1" snowfall on Wednesday. Our March total snowfall is hovering around just a half-foot. However, clear, cold, and calm conditions have contributed to a loosening of the upper snowpack and the small amount of snow we have. Skiing and riding conditions have been variable but have offered surprising quality, and tracks in the Pass indicate as much. Pay attention to these additional hazards as we shift gears into a windy, warmer Spring transition this weekend: 

• DRY LOOSE: It may still be possible to find areas with small amounts of recent snowfall over loose, faceted snow in isolated areas. In steep terrain, particularly on northerly aspects, you could sluff loose snow over firm surfaces below. These will not be large, but could knock you off your feet and send you somewhere you do not want to go. Look out for areas in steep terrain where this structure exists and manage your fall line accordingly. 
• WET LOOSE: If winds are less than forecasted, more intense sun and temperatures in the teens may make it possible to see some solar activity this afternoon or during the weekend. With cloudless skies and warmer temperatures, be on the lookout for signs of warming in the snowpack. Even a light, sustained breeze should keep this problem at bay, but with longer days and elevated solar input, do not be surprised if you see some isolated wet loose on southerly aspects in steeper terrain near rocks. 
• PERSISTENT SLABS: We are tracking several interfaces in the snowpack--small, weak, sugary grains between stiff, firm slabs in the upper snowpack, and the continued large and loose structure near the ground. We have not seen any activity on these layers since 1/31. However, it would not be outside the realm of possibility for a recently formed wind slab to "step down" to a weaker layer in the snowpack in the right spot. We will continue to monitor our poor structure as Spring develops, as these dormant layers could come into play with rapid loading of the snowpack, should it ever occur. 

Finally, as mentioned earlier, we are still experiencing a low-snow year. Be on the lookout for shallowly buried hazards like rocks, shrubs, or mining debris. 

RECENT AVALANCHES: 

Last week, HPAC staff and the public observed several natural dry loose sluffs and shallow pockets of wind slab at upper elevations in steep terrain.  The previous week, an Alaska Avalanche School motorized course triggered and reported a small D1 wind slab avalanche in Upper Willow at 3,800' on a SE aspect. Several other snowmachining parties were able to kick off small, shallow wind slab avalanches on 3/10 (see photo) near Grizzly Pass. Ski tourers on the Bomber observed some isolated sluffs and a shallow wind slab. Since 3/10, we have seen little noteworthy avalanche activity. See all recent observations here.