Turnagain Pass

Another spring day is on the doorstep. Although some high clouds should filter through and patches of valley fog are expected, many slopes should see a good dose of sunshine today. Without a big temperature increase expected, we are back into a Normal Caution regime in our core forecast area of Turnagain Pass. That said, paying attention to any unforeseen changes in weather, especially warming, is always critical.

Normal Caution avalanche issues to keep in mind:

Wet loose avalanches:  Solar aspects should heat up enough to soften surface crusts by the afternoon. If and when this happens, triggering wet sluff on steep sunny slopes will be possible. Natural wet sluffs are also possible in steep rocky terrain that is baking in the sun and saturating the snow surrounding rocks/vegetation.

Dry loose avalanches:  Many shaded steep slopes harbor loose faceted surface snow. If headed into this terrain, watch your sluff.

Wind slabs:  There was a 5-hour period of moderate westerly winds early this morning along ridgelines. Although there is not much loose snow for the winds to transport, it’s still prudent to keep a lookout for any new wind slabs that may have formed. Also, there could be some old lingering wind slabs that may still be reactive.

Cornices:  This is the time of year cornices will slowly warm and start to peel off. Give these guys a good margin from above and limit exposure below.

Glide avalanches:  A few new glide cracks have been seen opening up. Just one more thing for us to keep our eye out for as spring progresses.

Triggering a large slab avalanche that breaks in weak old faceted snow deeper in the snowpack remains a concern in areas that have a shallow overall snow depth. These areas are south of Turnagain Pass and include Johnson Pass to Silvertip area, Summit Lake and Palmer Creek. Watch for areas that have a harder wind packed layer of snow over weak sugary snow. Additionally, southerly facing slopes that are heating up during the day are more likely to avalanche once the surface crusts soften.

As always, practice safe travel protocol. Exposing one person at a time, watching our partners and having an escape route planned.

Facets found a foot below the surface in a shallow, wind scoured, area on Magnum. The total snowpack here was only 20″, yet it was over 6′ thick just 100 yds away.  This pit resembles areas to the south of the Pass and in Summit Lake where the general snowpack is thinner and more concern exists for triggering a persistent slab avalanche. 3.18.20. Photo: Jamie Lyons