|Travel Advice||Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.||Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.||Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential.||Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.||Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.|
|Likelihood of Avalanches||Natural and human-triggered avalanches unlikely.||Natural avalanches unlikely; human-triggered avalanches possible.||Natural avalanches possible; human-triggered avalanches likely.||Natural avalanches likely; human-triggered avalanches very likely.||Natural and human-triggered avalanches certain.|
|Avalanche Size and Distribution||Small avalanches in isolated areas or extreme terrain.||Small avalanches in specific areas; or large avalanches in isolated areas.||Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.||Large avalanches in many areas; or very large avalanches in specific areas.||Very large avalanches in many areas.|
|Signal Word||Size (D scale)||Simple Descriptor|
|Small||1||Unlikely to bury a person|
|Large||2||Can bury a person|
|Very Large||3||Can destroy a house|
|Historic||4 & 5||Can destroy part or all of a village|
Wet Loose: Spring is here and with it comes daily fluctuations in the avalanche danger with sun and warming. Timing is everything. Clear skies overnight have created a surface crust adding strength to the snow. As the day heats up and the crust melts and loses strength, the danger rises – making it possible to trigger a wet avalanche on steep sun exposed terrain features. Today looks similar to yesterday with daily temperatures expected to reach the mid-40F’s by early afternoon and little to no wind. Remember solar noon is around 2pm and this is when wet avalanches can begin to release, either naturally or by a person. Once the snow becomes wet and ‘mushy’ and your skis or snowmachine start trenching into wet snow, it’s time to find supportable surfaces. Even a small wet avalanche can turn into something larger in bigger terrain.
Wet Slab: There remains some uncertainty around the possibility of triggering a wet slab avalanche as warm temps today make the snow wet in the mid elevations. Earlier this week many natural wet loose and wet slab avalanches occurred below 2000′ where rain saturated the snowpack. As water drains out of the snow and we experience several days of re-freezing overnight this is becoming less likely, but not out of the question.
Cornices: Daily warming and sunnier weather can make cornices more unstable. As always, give cornices plenty of space and limit exposure underneath them.
Widespread natural wet avalanche cycle occurred below 3000′ throughout our region. Note the wet slab at 1500′ on South face of Tincan.
Pay attention to how supportable the snow feels in the afternoon as surface crust melt and the snow becomes wet. Yesterday it was easy to post hole up to your waist on Southerly aspect below 2000′.
Most of the large wet avalanche from 4/10-4/11 on Seattle Ridge were on the Southern end of Turnagain Pass where a generally thinner snowpack exists. Some of these avalanches released near the ground.
Triggering a lingering storm slab or a persistent slab is becoming less likely with time. However afternoon warming adds an element of uncertainty as surface crusts break down and destabilize the snow on solar aspects. Yesterday a group of 3 skiers experienced a collapse (whumpf) at 3000’ on a SW aspect of Tincan, and the day before a skier triggered a storm slab on a West aspect of Johnson Pass near 4900’. We know of older weak snow (facets) buried within the top 2’ of the snowpack and we don’t have a lot of info about how this snow is adjusting in the upper elevations. Northerly aspects with dry snow (without a surface crust) may harbor this set up. Basically triggering slab avalanche 1-2’ deep should still be on your mind if venturing into steeper terrain in upper elevations.
Yesterday was clear and sunny and no precipitation was recorded. Temperatures reached 50F near sea level and mid 40F’s in the mid elevations. Ridgetops were in the mid 30F’s during the heat of the day. Temperatures crept into the upper 20Fs at ridge tops and mid 30F’s at lower elevations. Winds were light from the Northwest 5-15mph.
For today expect sunny skies and another warm day. Temperatures should again reach the low 50F below 1000′ and 40F’s along ridgelines. Winds will be calm to light (0-10mph) from the NW. Temperatures are expected to be in the low 30F’s overnight.
For Sunday and Monday sunny weather will remain with diurnal temperatures swings, cooling overnight and warming during the day . Ridgetop winds are supposed to remain light from the Northwest. There is a possibility for light rain starting Wednesday associated with a low-pressure developing near the Aleutians.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||41||0||0||68|
|Summit Lake (1400′)||37||0||0||24|
|Alyeska Mid (1700′)||40||0||0||65|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||*N/A||NW||5||21|
|12/02/23||Turnagain||Observation: Seattle Ridge||Schauer / Keeler Forecaster|
|12/02/23||Turnagain||Observation: Tincan South Side||Anonymous|
|12/02/23||Turnagain||Observation: Eddies up track||Luc Mehl|
|12/01/23||Avalanche: Sunburst||John Sykes Forecaster|
|12/01/23||Turnagain||Observation: Eddie’s trees||Anonymous|
|12/01/23||Turnagain||Observation: Turnagain – God’s Country||Graham Predeger Forecaster|
|11/30/23||Turnagain||Avalanche: Tincan Trees||Kakiko Ramos-Leon|
|11/27/23||Turnagain||Avalanche: Tincan Ridge||Schauer/ Stiassny Forecaster|
|11/26/23||Turnagain||Observation: Road report: Slide with dirt on Repeat offender||Anonymous|
|11/26/23||Turnagain||Observation: Pete’s North||Ben Sullender|