Turnagain Pass

Was yesterday’s rain and snow enough to tip the balance for a widespread natural cycle? Or is our scary snowpack still lingering in place? 

Yesterday’s potent storm brought heavy rain to 2000’ and strong Easterly winds averaging in the 30’s with gusts in the 70’s. Precipitation amounts varied across our region favoring Girdwood with 1.5” of rain and Turnagain Pass seeing around .5” of rain. New snow totals in the upper elevations could range from 1-2+ feet. Visibility yesterday was poor and its unknown how much natural avalanche activity may have occurred. The Northern end of Turnagain Pass is likely to have higher snow totals similar to Girdwood. 

Incremental loading from multiple storms over the last two weeks in the Kenai Mountains have buried a reactive layer of weak faceted snow near the ground. Numerous human triggered avalanches have occurred almost daily since November 28th and today will be similar. The only difference is the slab is thicker and the consequences of getting caught are greater. Triggering an avalanche could propagate an entire slope releasing on the ground and running the entire slide path. Remotely triggering an avalanche from far away is also likely today, as seen two days ago at Tincan. See photos below. This is not an avalanche problem that can be out smarted or easily managed. Avoiding all runout zones and avalanche terrain steeper than 35 degrees is essential. Obvious signs of instability have been present all week including recent avalanches, collapsing ’whumpfing’, temperatures above freezing, heavy precipitation, and strong winds. Remember these red flags are evidence the snowpack is unstable. Today there will be a break between storms and if the visiblity improves be careful to not get tempted into avalanche terrain including small features with terrain traps. 

The avalanche on the left side of this photo was triggered remotely from 100’s of feet away by a party that re-grouped below Common bowl, Tincan SW aspect on Wed. Dec.6. A second avalanche also released on the opposite side of the ridge, a Northern aspect, at the same time. See photo below. This is a really scary snowpack set-up: A dense slab sitting on top of a persistent weak layer of facets connected by a slick bed-surface. Expect this problem to persist through the weekend.     

Remote triggered avalanche on a Northen aspect of Tincan, opposite side of the ridge from the avalanche in the above photo. The starting zone of these two avalanches is around 2500′.  

Strong Easterly winds have loaded leeward aspects, cross loaded many gullies and loaded corniced ridges. Human triggered wind slab avalanches or cornice falls are likely, but what is more of a concern is the potential for one of these to trigger a much larger and dangerous persistent slab avalanche as discussed above.  AGAIN today is not the day to be pushing into avalanche terrain! 

Rain on snow has occurred in the mid elevations (1000′ – 2000′) and wet loose avalanches are possible today. Above freezing temperatures may keep this avalanche problem lingering throughout the day and is an additional reason to avoid being on or underneath steep slopes. Although not much snow exists below 1000’ a wet avalanche from above could run into this zone. 

A view of Magnum’s West face from yesterday around 3:30pm. Several small slabs released below 2000′. This area is on the Southern end of Turnagain Pass and has recieved lower rain and snow amounts.