Storm Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Likely
- Größe
- 1.5–3
After a 3-day onslaught of warm, wet, and windy weather, skies should be clearing today. A few snow flurries may fall, but for all intents and purposes the precipitation should be wrapped up. Ridgetop winds however are still blowing 20s mph with gusts near 40 from the south where they are expected to remain until backing off this afternoon.
Recent Avalanches: Widespread natural avalanche activity was seen/heard over the past 2 days. Much of this was in the Girdwood Valley where the most snow fell. Summit Lake was also reported to have several large avalanches. However, due to poor visibility we don't know much of what occurred yet in many places, especially Turnagain Pass.
Estimated storm totals since Friday:
- Girdwood: ~6" snow water equivalent (SWE)/4-5' snow
- Turnagain Pass: 2-3" SWE/18-30" snow
- Summit Lake: ~2" SWE/18-24" snow
- Seward/Lost Lake: 2-3" SWE/24-30" snow
Today is one of those 'first day after a big storm' days. This means our hackles should be up. We did a quick trip into the Tincan Trees yesterday and found the storm snow was bonding well, great sign. BUT, this is only one small spot that is sheltered from the winds. We still need to approach each slope with caution and look for any signs of unstable snow. These signs would be cracking in the snow around you, collapsing/whumpfing of the snowpack under you, or recent avalanches. Some slopes could still be getting wind loaded today, which would make them more prime to avalanche. Here is a quick rundown on the various types of avalanches someone could trigger today:
Storm Slab Avalanches: On sheltered slopes where the new snow has not bonded yet, storm slabs could be triggered. These would be anywhere from 1-3' deep and related to how much new snow fell in that location.
Wind Slab Avalanches: Strong easterly winds during the storm have formed wind slabs in the higher elevations as well as exposed areas in the mid elevations. Continued winds along the higher terrain could continue forming wind slabs today. Wind slabs could be many feet deep and span entire slopes.
Cornice Falls: Cornices could be teetering on the brink of failure. These can be disastrous in themselves, but could also trigger an avalanche below, creating a worse situation. Give cornices a very wide berth.
Buried Weak Layers? The Summit Lake area has a plethora of buried weak layers. Please check that forecast if headed that way. Some of these layers may exist on the south end of Turnagain Pass and in the Johnson Pass/Silvertip zone. Something to keep in mind as we enter a week of clear weather and easier travel to outlying areas.