|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.
Cool temperatures and mild weather this week have been helping the snowpack adjust to a storm that left 6” to 30” of snow throughout our region last Sunday (3/19/17). Slope testers have been hitting the slopes hard and its been several days since any avalanche activity has been reported. Most of these avalanches have been small slabs, not well connected, and have been mostly on solar aspects during the heat of the day. This serves as a good reminder to pay attention to surface conditions as daily warming and sun may cause a sun crust on Southerly aspects to break down. Today’s cloud cover (if thin) and temperatures in the high 20F’s could act as ‘green house’ – trapping warm air. Should you notice wet surface snow or roller balls, it may be possible to trigger a wet avalanche in the afternoon. In Placer/Skookum where snow totals were deeper (2+’ deep), unexpected warming today could ripen the conditions for a bigger avalanche in this zone. Any natural or human triggered wet loose activity will be a sign to avoid steep Southerly slopes in the afternoon. Also be aware of the following avalanche problems:
LOOSE SNOW AVALANCHES (SLUFFS): Human triggered dry loose snow avalanches continue to be easily triggered on steep slopes without a sun crust on the surface. Watch your sluff if headed to steep terrain with loose surface snow, they could be larger and run further than expected.
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.
Although this avalanche was from a earlier in the week, if the sun crust starts to become wet today, triggering a wet avalanche may be possible.
One of several glide cracks opening up in Lynx Creek on a Southeast aspect.
Yesterday skies were clear. Temperatures in the morning were around 10F increasing into the high 20F’s by mid afternoon. Temperatures in the alpine reached 20F. Winds were light from the East and no new precipitation occurred.
Today skies are expected to be mostly cloudy with isolated snow showers, but the sun may still pop out at times. By this evening more cloud cover is expected and up to an inch of snow is possible. Daily temperatures swings are expected to range from 20F to 30F by mid day. Ridge top winds should remain light (5-10mph) from the East.
Tomorrow scattered snow showers are likely. Similar temperatures are expected, 20F – 30F, with light winds out of the Northeast, 5-10mph. The next few days look similar. A pattern shift is expected later in the week bringing warmer temperatures, but a good deal of uncertainty remains as to how much precipitation.
|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