Turnagain Pass

There were several fresh piles of wet loose avalanche debris observed yesterday that occurred on either Mar 7th or 8th. These were isolated to steep southerly slopes and examples of both natural and human triggered avalanches were observed. The last larger slab avalanche that we know of was skier triggered on Monday in the Johnson Pass area on the far southern end of the forecast zone (see Wednesday’s forecast for a good photo).

Two fairly large wet loose avalanches in the Crow Creek area that released naturally from the rocks and triggered small pockets of deeper slab avalanches midway down the slope. Photo 3.8.23 from Allen Dahl.

Several skier triggered wet loose avalanches that pickup up steam and left some sizable debris piles on the SW shoulder of Max’s in Girdwood. Photo 3.8.23

The temperatures dipped back below freezing last night after three days of a strong temperature inversion which created some premature spring like wet snow conditions. Today the temperatures are expected to remain below freezing throughout the day at upper elevations which should slow down the onslaught of wet loose avalanches that have been releasing both naturally and from human triggers the past few days. Wet loose avalanches could still be possible on steep south facing terrain in the afternoon but we do not expect them to be as large or widespread as they have been the last few days.

We are currently on the brink of being at low danger at all elevations, but just as the warm temperatures departed a new round of NW winds picked up overnight. Thanks to the prior round of NW winds that impacted the area last weekend the snow surface is already largely wind affected which should limit the amount of snow available for transport today. However, with weather stations already reporting gusts of 30+ mph this morning it is important to have wind slabs on our radar today at upper elevations. Natural and human triggered avalanches up to 1′ deep are possible in areas that are receiving active wind loading. This wind direction commonly has the greatest impact in areas along Turnagain Arm and on upper elevation ridgelines. To identify features with fresh wind slabs you can use small test slopes to check for shooting cracks and look for areas where the snow is visibly being transported by the wind.

Cornice fall is also possible with the combination of active wind loading and sunny skies. Be aware of any large cornices overhead and try to minimize time underneath them, especially if they are being wind loaded or baked in the sun.

Glide cracks have been opening up over the past several weeks. These things have a mind of their own and can release under any conditions, so it is important to be aware of any glide cracks overhead and try to minimize time spent underneath them.

Snow surfaces on shady aspects are already pretty wind affected, so today’s winds might not have as much loose snow to transport into fresh wind slabs. Photo 3.8.23

Areas of the forecast zone with a thinner snowpack, like near Johnson Pass, are still harboring persistent weak layers that could cause a larger avalanche. The last know avalanche on one of these layers was in the Bench Peak area and was skier triggered on Monday. We also have received reports of whumphs and seen some unstable snowpack structure from test pits on Pete’s N in the past week. This area typically gets a lot less snow than most of the forecast zone which can make persistent weak layers last longer and be more easily triggered by the weight of a skier or rider. Extra caution and careful evaluation of the snowpack is recommended if you are travelling in these areas.