|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.
|Size (D scale)
|Unlikely to bury a person
|Can bury a person
|Can destroy a house
|4 & 5
|Can destroy part or all of a village
The barrage of warm and wet weather continues today with light precipitation expected throughout the day and above freezing temperatures up to about 2000′. Yesterday, Turnagain Pass escaped from the worst of the rain and had surprisingly good weather (albeit warm) for the better part of the day. At the road elevation about 6″ of fresh moist snow fell in the early morning hours increasing to about 10″ at higher elevations where the snow was drier. In more coastal areas of the forecast zone, like Portage and Placer, rain fell throughout the day up to about 2000′. Strong winds accompanied the precipitation and was actively transporting snow at upper elevations creating fresh wind slabs which are likely for a skier or rider to trigger today, especially at higher elevations where the winds were stronger and the snow was drier.
Thanks to the warm temperatures the new snow seemed to be bonding to the existing snow surface quite quickly, but we were able to trigger shooting cracks on steep wind loaded features near treeline. We recommend watching for signs of active wind loading today to identify areas with touchy wind slabs and using test slopes to determine how reactive the wind slabs are before entering into consequential terrain. With a lot of snow available for transport yesterday there are probably some large wind slabs lurking in the upper elevations. Marginal visibility could make it difficult to see the slopes above you today but it is safe to assume that upper elevation start zones will continue to be loaded as precipitation and moderate winds continue throughout the day.
Overall, we have seen mostly right side up and stable snowpack structure recently but a surprising human triggered avalanche on Tincan Proper on Thursday is a good reminder that it is still possible to trigger an avalanche on a deeper layer of facets above the New Years Crust (see ob here). This avalanche was 2-5′ deep and propagated across a ridgeline in very consequential terrain. Luckily everyone was okay, and this near miss was an opportunity for us to reevaluate where the facets over the New Years crust are most likely to be triggered. Our best estimate is that the New Years crust is more supportable at higher elevations which provides a cleaner bed surface for avalanches to run in the facets above the crust. It will be easier to initiate an avalanche on this layer in areas with a thinner depth to the weak layer, so we suggest that you take time to evaluate the snowpack structure at upper elevations before entering avalanche terrain.
Cornices: All the recent wind transport also means that cornices were building and could be sensitive to human triggers today. They often break further back than expected, so give a wide berth when travelling along corniced ridgelines.
Loose Wet Avalanches: With rain falling up to 2000′ it is likely that wet loose avalanches are releasing in steeper terrain, especially in more coastal areas that saw higher amounts of rain on snow yesterday. This type of avalanche often has more force behind it than you might expect so be aware of the potential for a wet loose avalanche to push you downhill if you are on steep slopes in an area with a water saturated snow surface.
Yesterday: Above freezing temperatures up to about 2000′ across the area with rain and wet snow. The rain was mostly concentrated near the coast (Portage, Placer, Seward) and areas inland were largely spared from the worst of it. About 6″ of moist snow at the road elevation in Turnagain with up to 10″ as the snow became drier at higher elevations. Winds stayed strong for most of the day with averages around 40 to 50 mph until 10 am and then dropping down to 30 mph until 10 pm on Sunburst.
Today: Another day of above freezing temperatures up to about 2000′ and light precipitation throughout the day. Total precipitation should be around 0.2″ water with snow line around 2000′. Areas closer to the coast will see much higher precipitation totals today, similar to yesterday. Winds will remain moderate in the 15 to 30 mph range and gusts to 50 mph. Visibility looks poor today, but yesterday Turnagain was in a blue hole for a good portion of the afternoon, so maybe we will get lucky again.
Tomorrow: Sunday looks like a repeat of Saturday’s weather. Warm temperatures up to 1500 – 2000′ with light precipitation throughout the day. Winds will start to increase ahead of the arrival of the next major pulse of moisture, which looks like it will hit our area Sunday evening through Monday evening. Precipitation amounts are forecast to be much higher from Sunday evening to Monday evening.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)
|Snow Depth (in)
|Center Ridge (1880′)
|Summit Lake (1400′)
|Alyeska Mid (1700′)
RIDGETOP 24-hour data (6am – 6am)
|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