Turnagain Pass Avalanche Forecast

Today marks a significant pattern change in our weather from the cold, dry high pressure of the last several days to another warm, moist air mass spilling into south-central Alaska. The two factors effecting stability the most today will be rapidly rising temperatures and rain; potentially up to 3,000’.

Wet slab avalanches will be possible to trigger as yesterday’s dry surface becomes saturated at elevations below the rain/ snow line.  These may be up to 2’ deep and conceivably could step down into buried weak layers that we know exist throughout the Turnagain and Girdwood Valley zones.  Below 2,500’ our snowpack is strong and lacks energy.  That being said, the surface has already seen rapid warming at this elevation band and as it becomes saturated with rain later in the day, skiers will be able to initiate wet loose ‘push-alanches’ and point releases in steep terrain, though a cohesive slab will be unlikely at this lower elevation band. 

Perhaps more concerning for today; temperatures began their climb across the forecast area yesterday with some dramatic upticks in the mercury this morning (9 deg F in 12 hrs @ Center ridge, 18 deg F in 12 hrs @ Grandview and 28 deg F in 12 hrs at Granite!).  This is a big red flag as rapid warming such as this leads to a loss of strength within the snowpack. Though not as dramatic yet (7am) at ridgetop locations, if temps continue to increase throughout the day, particularly in the upper elevations, expect avalanche danger to follow suite with wet slabs becoming more likely.

Temperatures, winds and RH are all on the rise today throughout the forecast area.

Today’s new load is unlikely to be enough to tip the balance and initiate a persistent slab.  However, the warming trend over the past 24hrs is acting to decrease the strength of buried weak layers.  Rapid warming combined with the potential for a skier-triggered wet slab to step down into buried weak layers has us continuing to keep an eye on this avalanche problem.  

With very little snow available for transport, wind slabs today will be relegated to the upper elevations and comprised of new snow.  These will grow throughout the day above the rain/ snow line and expect them to become increasingly sensitive to human triggers as the storm progresses. As of 6am this morning ridgetop winds are gusting to 60mph in advance of precipitation.