Turnagain Pass

We heard of one snowboarder triggered avalanche yesterday. This was on the SW face of Magnum and pictured below. It was seen by a group further away and reported that the rider was caught but then able to ride out of the way. Although unknown, this was most likely a fresh wind slab avalanche. UPDATE at 8:50am – group involved sent in their report HERE. It was indeed a wind slab ~100′ wide, 6-12″ deep, and ran ~300′.

Skier triggered avalanche on the southerly aspect of Magnum. Note the skier on the bottom left. Photo taken from the saddle between Magnum and Cornbiscuit, 2.25.23.

It looks like one more day of NW outflow winds before things quiet down tomorrow. If you are headed out to enjoy the sunshine and the chilly temperatures, keep an eye on where the winds are blowing – as wind slab avalanches are the main concern. Slopes with recent wind loading will be much more dangerous than areas out of the wind. This NW flow direction can split around certain zones/ridges, blow from all kinds of directions in channeled terrain, and even miss some zones if we are lucky. This can happen for portions of Turnagain Pass. Hence, starting from your drive, be on the lookout for what the winds are doing.

Once in the snow, keep an eye out for where winds have drifted snow. Does the snow feel stiff, hollow, or drumlike? Are there cracks that shoot out from your skis/board/machine? All these are clues you’ve found a wind slab and if the slope is steep enough it could slide. Wind slabs are likely to be in the foot deep range and touchy. That said, triggering a wind slab avalanche will be likely on freshly wind loaded slopes.

Cornices are also a concern. Giving them an extra wide berth is prudent. Remember, they can break further back than we might think.

Sun Effect:  With temperatures in the teens to single digits, the sun isn’t likely to heat those southerly aspects that are out of wind enough to create sun triggered sluffs or reactivate old weak layers. However, this idea should always be in the back of our minds this time of year.

Winds blowing southerly on the lower Tincan Ridge yesterday (terrain channeling as the main winds are NW along the higher peaks). Note the wind effect on the snow surface. Thanks to AK Guide Collective for the photo, 2.25.23.

In the top 2-3′ of the snowpack there are various layers of old buried surface hoar and small facets. Although we have not seen many avalanches break in these layers in general, the last one was a week ago in the Tincan Library. It’s still something we have on our radar. Triggering an avalanche in one of these layers is becoming unlikely, yet that does not mean there could be surprises out there. If we are hunting for areas sheltered from the wind today, this is a good reason to always pay close attention to any signs of instability (whumpfing/collapsing and cracking in the snow around you). It is also a good reason to always have good travel protocol, meaning exposing one person at a time, having escape routes planned, watching our partners, and having a plan if the slope does slide.

In areas with a thinner snowpack there are weak layers near the base of the snowpack that remain a concern. After getting information from the southern end of Turnagain Pass last week and in Lynx creek, it appears this deeper snowpack issue is mostly out of our forecast zone and in the Summit Lake area. Therefore, we’ll keep talking about it, but mainly in the Summit Lake section of the Bottom Line above.