|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.
Yesterday was the first day since last weekend’s storm that avalanches were not reported. It has been five days since the storm ended and the weak surface snow (near surface facets and surface hoar) from the March high pressure/drought was buried. Slab depths vary across the advisory zone due to the range of storm totals from 6″ to 2+ feet. Most of the avalanches that have occured have been small human triggered pockets and not well connected; a testament to the relatively cold weather this week keeping the new snow loose and mostly unconsolidated. The slabs that have released have been in places where the slab is more cohesive, either due to wind effect or warmth/settlement. On Thursday one of the avalanches that was observed was thought to have been a natural that occured later in the day from warming and direct sunshine.
For today, with similar weather to the past few days, we can expect similar avalanche conditions. Triggering a slab avalanche is still possible. Things to keep in mind are:
Snow pit on Tincan Common. APU Snow Science Class
LOOSE SNOW AVALANCHES (SLUFFS): Human triggered dry loose snow avalanches continue to be easily triggered on steep slopes without a sun or wind crust on the surface. Watch your sluff if headed to these steep lines with loose surface snow, they could be larger and run further than expected. Pay attention to Southerly slopes as the afternoon temperatures become warmer. We could start seeing more wet loose avalanches from direct sunshine; cold temperatures have keep these to a minimum lately. Look for roller balls as an indication of surface snow warming.
CORNICES: There has been a couple of cornice breaks after the storm and cornices are always worth giving a wide berth. Direct sunshine and warming can help to loosen them.
GLIDE CRACKS: Glide cracks continue to slowly ooze open on Seattle Ridge, Tincan’s Library, Lynx creek and other zones. Keep an eye out for them and limit time spent underneath.
Sluffing on Magnum observed on Wednesday.
Yesterday was sunny and clear with temperatures in the 20Fs in the valleys and teens at ridgetops. Winds were light and variable. Temperatures dipped into the single digits overnight and skies were mostly clear.
Today the sunshine will continue with a similar temperature pattern and winds will remain light. Clouds are forecasted to roll in this evening and there is a chance of snow overnight.
Tomorrow will be mostly cloudy with a chance of snow showers and slightly warmer temperatures. According to the National Weather Service “Real change continues to be advertised by all models early into next week and the bottom line is that the pattern is now on the verge of change and the days of cold and endless sun are going on a brief hiatus.” The track of the low moving into the Gulf is still uncertain. Stay tuned!
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)
|Snow Depth (in)
|Center Ridge (1880′)
|Summit Lake (1400′)
|Alyeska Mid (1700′)
|Temp Avg (F)
|Wind Avg (mph)
|Wind Gust (mph)
|Seattle Ridge (2400′)
|Observation: Kickstep NE Bowl
|Observation: TinCan Backdoor/ Center Ridge
|AAS L1 Turnagain
|Avalanche: Lynx Creek
|Observation: Turnagain, Seattle, Mt Ascension
|Silverton Mountain Guides
|Observation: Tincan Trees
|Dalpes/Thamm/ Schauer Forecaster
|Observation: Seward Highway across from Johnson Pass TH
|Avalanche: Base of Seattle Ridge
|Troy Tempel, Thomas Lees, .Josh Bollaert, Damian Naquin
|Observation: Lynx creek