Turnagain Pass

After many natural wet loose avalanches occurred on Saturday, only a few were reported over the past two days. The last dry snow avalanche that we know of was the slab triggered on the upper face of Captain’s Chair. Take a minute to read that report HERE.

As spring slowly moves back into Alaska, the snowpack is beginning its transition from a cold dry snowpack to a summer melt-freeze one. With chilly nights and warm days, the transition is slower than if we were to get rainy warm weather. During these spring transitions we often see large wet snow avalanches, but that is probably still a week or two away. Until then, a smaller variety of wet snow avalanches in the top foot or so of the snowpack is the main concern. This is why paying close attention to melting surface crusts and soggy snow late in the day is important. This includes considering your exit route as the prime time for wet loose slides are between 3 and 6pm.

Beginning with east facing slopes, then south, and last westerly aspects, small to medium sized wet loose, and even shallow wet slabs, can be triggered by us or could release naturally as the day progresses. This will be more pronounced tomorrow, Wednesday, as warmer temperatures are expected tomorrow afternoon/evening. Once the surface crusts melt enough that your boot sinks down 6″ or more into soft wet snow then these wet loose slides on the steeper slopes are possible and it’s time to head to a cooler aspect.

Wet loose avalanche on Seattle Ridge from over the weekend. A great example of snow heating up around dark features (rocks/vegetation) to the point small chunks of soggy snow roll down the slope and entrain enough additional wet snow that the next thing you know there is a wet loose avalanche. Photo taken on Monday, 4.17.23.

Lingering Wind Slabs:  For those seeking the dry snow in the higher elevations, lingering wind slabs or some kind of surprise dry slab avalanche could be found. Weather stations have not shown strong enough winds to move snow since early Sunday morning, so any dry slab should be fairly stubborn. That said ,in steep rocky terrain where slopes are unsupported from below, this is the ideal place to find one of these older slabs. The slab triggered last Saturday on Captain’s Chair was most likely an older wind slab.

Cornices Falls:  Cornices tend to slowly ooze over during the warm weather and can become more likely for us to accidentally cause one to break off. Give these an extra wide berth and limit time under them.

While the main avalanche concerns lie in the upper snowpack, there is still a suspect layer of rounding facets buried 3-6′ deep. This layer was responsible for many very large human triggered avalanches in the second half of March, but we have not seen any activity on it for three weeks. Although it would be very unlikely to trigger an avalanche this deep now, we are keeping in the back of our minds, especially as the snowpack slowly warms. Once the snowpack starts seeing significant warming, we are anticipating some big wet slabs in the future.