Turnagain Pass Avalanche Forecast

Widespread natural wet loose and wet slab avalanches have been seen over the past 4 days (video below). With cloudy skies yesterday and limited observations, we only know of a few new confirmed natural avalanches, these were mostly seen in the Summit Lake area. There have been a few slabs releasing on northerly aspects as well. One in Girdwood Valley that released on a northerly aspect late Sunday and another in Summit Lake, north of Manitoba.

As for human triggered avalanches, a snowboarder triggered a wet sluff on the backside of Seattle Ridge on Sunday (photo below). They were caught when trying to evade their sluff and described the experience this way: “pushed me down the face like a bulldozer”. Later the rider said it was not a good feeling being pushed by so much weight and ‘no joke’.

Snowboarder triggered wet loose on the backside of Seattle Ridge. Circles mark where the rider triggered the sluff and where they ended up at the toe of the debris. 4.18.21. Will Morrison. (Thanks Will for sharing!)

Glide avalanche that released on Sunday midday, just 300 yards to the south from the motorized up-track on Seattle Ridge. 4.18.21. Brent Byrne. 

The springtime transition continues with more natural avalanche activity expected today. After three days of intense sunshine and warm temperatures at all elevations, clouds moved in yesterday with strong east winds and a trace of rain to 2,000-3,000′. That front is headed out today and some sunshine should start making its way back in by the afternoon. Last night’s refreeze is likely to be slim to none with the cloud cover. It should not take much solar input today, even with some cloud cover, to melt any crusts and continue the wet avalanche cycle we’ve been seeing.

Aspect: Most of the natural avalanche activity has been on east, south, and west aspects due to the direct sunshine. However, there have been a few reports of slabs releasing on north aspects. With those reports, coupled with cloudy skies last night warming all aspects, and early morning and late evening sun hitting northerly terrain, we need to be aware that some north aspects could start losing their strength and begin to avalanche.

Steering clear of slopes with wet, mushy and saturated snow and being out from under any overhead hazards are key. As you can see in the video, steep rocky terrain is shedding its snow easily and it’s not a time to be under this type of terrain or any cornices for that matter. Cornices are peeling away and even a small chunk that falls could initiate a large avalanche. Steep slopes we’d like to ride or ski should be avoided when the surface snow is ‘punchy’ with several inches to a foot or more of wet saturated snow. Triggering a wet sluff can be easier than might be thought and very difficult to escape from. Triggering a wet slab is likely as well, and much more destructive. We have seen many small wet loose avalanches initiate wet slabs and this pattern should continue.

Timing is everything: After today, we should start back into a springtime melt/freeze cycle. This is good news for those interested in corn snow conditions. As skies clear back up we can expect wet surface snow to freeze at night and melt during the day. Avalanche danger will follow this pattern: lower danger in the early morning when the snow is frozen, higher danger as the snow melts and loses its strength during the day.

On upper elevation north aspects that have mostly dry snow, we are concerned that a person could trigger a dry slab avalanche in the 2-3′ deep range. Even if the top inch or two of snow is moist or wet, there can still be dry snow issues below this. There are old weak layers from March and possibly there could be weak snow under last week’s storm snow. Looking for signs of instability and assessing the snowpack before committing to steep north aspects with little or no sun effect will be prudent.

Glide cracks are popping… Several glide avalanches were reported and seen through the region from Girdwood to Seward over the past three days. As with the concerns stated above, avoiding being under overhead hazards includes glide cracks. Keep you eye out for them as several cracks are opening up each day. There are a few on Seattle Ridge we have our eye on.

Glide avalanche on Mt. Marathon in Seward. 4.18.21. Photo Anonymous.