Avalanche Activity

An active weather pattern continues for Eastern Turnagain Arm and another powerful storm is bringing strong winds and heavy snow to our region today. The National Weather Service has issued a Special Weather Statement due to 2-3 ft of snow expected in the mountains of Girdwood, Turnagain Pass and Moose Pass by Friday. Overnight Portage Valley has already seen 0.6 inches SWE (mix of rain and snow) and Turnagain Pass snow stake has ~4 in of new snow overnight. Today 12 inches of snow is expected for Turnagain Pass and Girdwood by early evening and another 1-2 ft of snow is possible overnight. Strong ridgetop winds 30-40 mph from Northeast will continue through the day and build into the 60s mph and gusts in the 80s mph by this evening. This means the avalanche hazard will be increasing throughout the day and natural avalanches will be more likely as today’s storm progresses. The more snow that falls the greater the avalanche hazard. With such strong winds storm slabs could grow to 1-2 ft in the alpine before dark. Below 2000 ft where a stout crust has formed storm slabs could be easily triggered on this slick bed surface as snowfall totals increase. Avoid all avalanche terrain if you see any natural avalanches and be prepared to end your day early due to increasing danger. 

Persistent Slabs: To compound today’s avalanche hazard, there is also weak snow (facets and buried surface hoar) buried under 2-3 ft of new snow from this weekend. Yesterday we heard about a skier partially buried in an avalanche between Placer and Grandview at around 4000 ft on NW aspect. According to a witness in the area the crown was 3 ft deep by 300 ft wide and the skier was partial buried, but okay. This is a good reminder that the size of the avalanche hazard is increasing from large to very large with the addition of more snow and strong wind today. This poor structure is most concerning above 2000 ft where a stout crust formed on Monday night.

South of Turnagain in Summit Lake a variety of old weak layers in the mid and base of the snowpack. The Southerly storm track direction is expected to impact Summit Lake with up to 1-2 ft of new snow by Friday. This wasn’t the case last weekend where only a few inches fell. Be aware that more uncertainty exists in this zone for triggering dangerous avalanche in a variety of old weak layers, and rapid loading from new snow and strong winds could also cause natural avalanches by this evening.

Wet Snow: A mix if rain and snow is expected below 1000 ft. In Portage and Placer Valley where above freezing temperatures mid-day could cause heavy rain, loose-wet avalanches are possible today in lower elevations.

View the full forecast at CNFAIC