Avalanche danger high as parade of storms targets Southcentral
The Chugach National Forest Avalanche Information Center (CNFAIC) warns of high avalanche danger in Turnagain Pass, Girdwood, and Portage Valley starting this evening as a parade of storms moves into Southcentral this week.
The storms, one after the next, will dump 2 to 3 feet of snow on parts of the Kenai Peninsula by Friday. The heavy snow combined with strong wind will make backcountry terrain exceptionally dangerous in the coming days.
In the coming days, parts of the Kenai Peninsula are forecast to get inches of moisture.
Meteorologists look at the snow/water equivalent, which is how much water would come out of the snow storm if it were rain instead. Parts of the Kenai will receive more than 6 inches of water by Friday. That is expected to be 2 to 3 feet of very wet, heavy snow in that time.
As the snow falls, there will also be powerful winds. Sustained winds will be around 30 to 40 mph in higher elevations with wind gusts topping 60 mph and nearing 80 mph at times. That will cause wind loading in the coming days.
Wind loading takes snow from the windward side of a mountain and deposits it on the leeward side. At times, the accumulation of snow can happen at almost 10 times the rate of snowfall. The blown snow loses its flake formation as collisions round it into smaller, sand-like pellets.
Wind loading will deposit a thick, dense layer of snow on top of an already poor snowpack, raising the danger of slab avalanches in steep terrain.
The CNFAIC warns of high avalanche danger in advance of heavy snowfall during the second half of the week. The high danger area includes Turnagain Pass, Girdwood and Portage Valley.
Human-triggered avalanches of one to three feet are possible Wednesday and will grow more likely in the coming days as snow continues to fall.
Natural avalanches will become more likely in the coming days as the snow accumulates.
Avoid areas with steep slopes and avalanche-prone terrain in the coming days. Places such as the Byron Glacier trail and Portage Valley run the risk of large natural slides propagating all the way to the valley floor.
Johnson Pass and Lost Lake have an already poorly structured snowpack. Incoming snow and strong wind will stress the already weak snowpack in the coming days.
Similar conditions will persist in Hatcher Pass in the coming days. Heavy snow and strong winds on top of an already poor snowpack will increase avalanche danger in the popular mountains. Before the snow even started flying, the Hatcher Pass Avalanche Center observed several early-week human-triggered avalanches.
Be sure to check conditions before venturing into the backcountry.
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