Anywhere between 6-16″ of new dry snow has fallen over the past 36 hours across the region. Girdwood Valley seemed to have picked up the most snow, with over a foot accumulating at the high elevations. Turnagain Pass and Summit Lake have both seen around 6-8″ of new snow. Easterly ridgetop winds have been 15-25mph, which is enough to load leeward slopes. That said, avalanche concerns will be relegated to the new snow. How much snow fell in the area you travel, how much wind loading occurred and how the new snow is bonding to the underlying surfaces are the questions today. High elevation northerly aspects are the most suspect for poor bonding as the new snow fell onto weak older snow and possibly surface hoar. If you are headed out today in hopes of the clouds breaking, keep the following in mind:
On all Southerly facing slopes and slopes below 2,500′ we can expect the new snow to stick rather well to the old soft/warm crusts. The concern here will be daytime warming and sunshine. Roller balls and wet loose sluffs should be expected as the new snow heats up and begins to roll and sluff off the mountainsides. The size of potential sluffs will be determined by the amount of new snow. Wet sluffs could become quite large and dangerous on slopes with up to a foot or more of new snow.
CORNICES: There are still large cornices along ridge tops. Give them lots of space as they can break farther back than expected.
GLIDE AVALANCHES: It’s been close to two weeks since our last known glide avalanche, but keep in mind glide cracks are continuing to creep down-hill. As always, limit traveling under their runout. They are unpredictable and can avalanche at any time.
Yesterday: Roughly 6-10″ of new snow fell over the region at all elevations late Thursday and early Friday morning, favoring Girdwood Valley. Light showers continued through the day adding another 1-3″. Ridgetop winds over the past 24-hours have been easterly 15-25mph with gusts to 40mph. Temperatures have been in the 20’sF along ridgetops and near 30F at 1,000′.
Today: Clearing skies and lingering clouds are expected today before a third round of precipitation pushes in tonight. Ridgetop winds should be in the 10-20mph range from the east today and bumping up to the 30’s tonight. Temperatures are on a warming trend and may reach 40F at 1,000′ today with ridgetops in the upper 20’sF.
Tomorrow: Stormy wet weather is on tap. Rain up to 1,500 – 2,000′ is expected tomorrow with 6-12″ of snow above this. Up to 16″ of snow could fall in favored areas such as Portage Valley and Girdwood. Ridgetop easterly winds will be in the 30-40mph range with gusts over 50. Unsettled and wet weather looks continue into the workweek.
Thanks to our NWS partners for their graphic of QPF (Quantitative Precipitation Forecast), which is the water amount expected through Sunday. A general rule of thumb is 1″ of water = 10″ of snow. Of course it has to cold enough for snow and this event is expected to bring rain up to 1,500′ with snow falling at the higher elevations.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||34||1||0.2||65|
|Summit Lake (1400′)||32||3||0.3||20|
|Alyeska Mid (1700′)||30||3||0.4||62|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||25||*N/A||*N/A||*N/A|