Turnagain Pass

Good morning. This is Kevin Wright with the Chugach National Forest Avalanche Information Center on Saturday, January 28th at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

BOTTOM LINE

The avalanche danger is MODERATE in specific wind loaded pockets in steep terrain. We saw one example yesterday of a significant avalanche in a cross loaded South facing gully. Much of the region where most people are skiing, on terrain less than 35 degrees and below tree line, has a LOW avalanche danger.

AVALANCHE DISCUSSION

Despite the cold weather, skiers and riders were out in full force yesterday. Most people were staying away from the big and steep terrain, so we still don’t have a great idea of what might happen in those areas. Our caution level is definitely waning, although one big piece of information from yesterday caught our attention.

For the most part the snow through Turnagain Pass is loose and relatively stable. Loose snow sluffing is common, but the sluff quickly slows down and stops in less steep terrain. Pockets of wind affected areas are common however, with stiffening of the top 4-6 inches. These areas will slab out if the terrain is steep enough, but we only saw one example yesterday where a wind slab produced a big enough avalanche to hurt someone.

That example looked to be up to 2 feet deep on a cross loaded South facing gully. See anCNFAIC Staff picture here. It broke mid slope and came out the bottom with significant force. There was no human trigger for this avalanche, although we are speculating an animal may have caused it. This is a big outlier in what we saw yesterday, but it illustrates the potential if you find a bigger and stiffer wind pillow in steep terrain. Your hackles should go up if you find a transition to significantly stiffer snow in terrain greater than 38 degrees. Route selection and terrain management will prevent problems today. Any bigger and steeper terrain should be approached with a healthy amount of skepticism if wind loading affected it.

There is scattered buried surface hoar in lower elevation drainages (below 1500-2000′). This is more prominent in the Girdwood Valley and northern side of Turnagain Pass and, what seems to be, less so in the southern Turnagain region. Our investigations Thursday on Max’s Mountain found it moderately reactive around 1500′. Collapsing, but no cracking/avalanching has been seen/reported on this layer to date – yet the layer exists and a person could get a surprise on a lower elevation rollover.

MOUNTAIN WEATHER

The clear and cold trend continues today. There is a slight inversion this morning with valley temperatures below zero and some ridgetop stations reading slightly above zero. Wind has been minimal since Thursday when the most recent wind slabs formed from gusts into the mid 30s from the East. Today the wind should be slight, and not enough to form more wind slabs.

Our next chance of snow will be Sunday night, with a change to cloudier weather and somewhat warmer temperatures.

CNFAIC Weather Page and the NWS forecast

I will issue the next advisory Sunday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.