If you are headed to Turnagain Pass you get to start your day with a red flag warning, a recent avalanche. Yesterday two skiers remotely triggered an avalanche on the Southwest face of Eddies from 30’ away on a flat ridge. They had just dug a pit and found the culprit, buried surface hoar, one foot below the surface. Multiple tracks were present along the ridge before the avalanche released no obvious signs like whumpfing were observered.
This is the same buried surface hoar “MLK BSH” we’ve been talking about for two weeks since it was originally buried on Matin Luther King Day. This weak layer is widespread across our forecast zone and has been responsible for numerous large human triggered avalanches over the last 10 days, all in Seattle Creek drainage, and not visibile from the road. So far no one has been caught or carried and most of these avalanches have been triggered remotely from an adjacent ridgeline. Yesterday was the first human triggered avalanche on the non-motorized side of the road. Today’s sunshine and soft snow could make it tempting to push into steeper terrain. Keep in mind incremental loading over the last week and period of stronger winds on Monday may have added more stress to this weak layer. Don’t forget this is a challenging avalanche problem to evaluate and manage, and warrents extra caution.
Keep in mind as you travel today:
South of Turnagain – Johnson Pass/Summit Lake zone: Areas south of Turnagain Pass harbor a thinner, weaker snowpack with multiple weak layers present, including the MLK buried surface hoar. This area also received additional snow on Sunday and Monday and elevated Easterly winds. Similar to Turnagain Pass an avalanche triggered in this zones could propagate an entire slope and be large enough to bury or kill a person.
Remote triggered avalanche on Eddies occured yesterday afternoon after mulitiple people had skied the ridge.
CORNICES: We had a report of a large cornice fall in upper Seattle Creek drainage over the weekend. Give cornices an extra wide berth as they often break farther back than expected.
LOOSE SNOW AVALANCHES (dry and wet): Daily warming and radiation from the sun could warm surface snow on steep Southerly aspects. Keep your eye’s out for roller balls or small wet-loose avalanches under rocks. On shaded aspects dry loose “sluff” is possible in steep terrain.
WIND SLABS: There is a lot of snow available for transport. Ridge top winds should remain light from the Southeast, but winds could puff up along some localized upper elevation zones. Should you see drifting snow, expect any recently wind loaded feature to be tender. Any wind transport will also be adding stress to a larger more dangerous avalanche problem, where triggering a small wind slab could step down into a deeper more dangerous layer.
Glide cracks are opening again. We know of one glide avalanche that has released recently in the Summit zone just north of Manitoba. Look out for glide cracks and limit exposure under them!
Yesterday: Thick valley fog was observed below 2000′. Above this elevation skies were partly cloudy. Temperatures remained around 30F near sea level and mid 20Fs near ridgetops. Ridgetop winds were light and variable. No new precipitation.
Today: Valley fog will continue through the morning and may burn off in some areas by the afternoon. Above the fog skies will be partly to mostly sunny. Daily warming will cause temps at sea level to increase from mid 20F’s to low-30Fs. Upper elevation temps will be in the mid to upper 20F’s. Ridgetop winds from the Southeast will range from 5-15mph with gusts in the low 20’s mph. No precipitation is expected.
Tomorrow: A similar day is in the forecast with partly sunny skies. Daily warming and mild temperatures in the mid to upper 20F’s is expected. Valley fog is possible. No new precipitation is expected and ridgetop winds should remain light.
*The Seattle Ridge anemometer (wind sensor) was destroyed. We have a replacement on the way and it should be operational by mid February.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||26||0||0||58|
|Summit Lake (1400′)||20||0||0||27|
|Alyeska Mid (1700′)||25||0||0||52|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||26||*N/A||*N/A||*N/A|