Turnagain Pass Avalanche Forecast

Yesterday ridgetop winds 20-30mph were observed from the Northeast and will continue throughout the day. Isolated wind slabs up to 8” thick are possible on leeward aspects of ridges and terrain features. Due to the limited amount of snow available for transport these slabs will be small and are unlikely to bury a person. However if triggered in the wrong place it will be possible to take a ride over a cliff or through rocks. Use caution if traveling along ridgetops and avoid hollow sounding snow and pillow-like features on steep complex terrain. 

Wind slabs are likely to become thicker later in the evening with snowfall, up to 3″, forecasted for the upper elevations.    

It’s been just over a week since a layer of faceted snow was covered by a 2-3′ slab (post St. Patty’s Day storms 3/16 and 3/19) and widespread avalanche activity ensued. We have been talking about this problem extensively and the variable nature of where it exists and where it does not. In short, triggering a persistent slab is becoming more and more unlikely because 1) many slopes have either already avalanched, 2) the facets were blown away before the storm or 3) the slab/weak layer has adjusted. 

That said: there is still a remote chance a person could trigger a slab up to 2′ thick that fails in weak faceted snow. Shaded aspects with no surface crust are the most suspect. Safe travel practices are encouraged – expose only one person at a time on a slope and have an escape route planned.

Cornices:

Cornices have been growing over the last few weeks and today’s moderate Eastern ridgetop winds will continue their growth. If traveling near a ridgeline, be aware of cornice formations and give them lots of space. Steady moderate winds could increase the likelihood of cornice fall – thus avoid travel below cornices as well. 

Cornices like this one on Seattle Ridge have been getting larger over the last few weeks.

Wet Avalanches:

Overnight temperatures have remained above freezing (F) at mid and lower elevations. Rain will start later this afternoon and small wet loose avalanches on Southern and Eastern aspects below 2000’ are possible, yet should remain a low hazard.