Good morning. This is Kevin Wright with the Chugach National Forest Avalanche Information Center on Wednesday, March 14th 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).
New storm snow on top of weak older snow is producing CONSIDERABLE avalanche danger through the region. We can expect small to medium size natural avalanches in specific areas today. Human triggered avalanches will be likely above treeline and in areas receiving wind loading. Expert routefinding and conservative decision making will be essential to staying safe today.
Yesterday, Alaska had its first avalanche fatality of the year. Robert Liberman was killed while guiding heli-ski clients near Haines. One CNFAIC Staff person is reported as “clinging to life” from the same avalanche. We send our sincere condolences to the family and friends of those involved in this incident. While we don’t have the same snowpack as Haines, it’s a poignant reminder of the risks we all take by traveling in the backcountry.
Today is a huge weather change, and it deserves a healthy amount of respect for today and into the near future. This storm should be looked at differently than what we’ve had for the last 2 months, at least until we know how the new snow is going to react to the old surface snow. The surface snow was getting old and tired… Surface crusts, faceting, surface hoar, and wind hardening were all prevalent to varying degrees depending on location. All of these substrates will act as a poor bonding surface for the new snow falling today.
Concern #1 – Storm Snow
This is a no-brainer. Some areas have already gotten an inch of snow water equivalent since last night. That adds up to about a foot of new snow with wind loading, and snowfall is expected to continue today. As I mentioned before, we should expect this new snow to bond poorly to the underlying surface.
Concern #2 – Wind Slab
Areas with higher wind velocities and wind catchment features will have the highest probability of causing problems. With continued snowfall today it will be difficult to climb safely to high elevation areas where wind slabs are more likely to be found. Yesterday we found a very touchy, yet shallow wind slab off the West face of Lips. The 3-4 inch slab on top of loose faceted snow propagated 50+ feet wide very easily. Today that slab will be 1-3 feet deep and much more dangerous.
A solid Southeast flow is bringing a stream of moisture to our region through Prince William Sound. As of 6am this morning, up to 1 foot of snow has fallen in the Girdwood valley with less in Turnagain Pass. Wind is picking up with gusts into the upper 40s at ridgetops.
Snow and strong wind is expected to continue all day today. AnCNFAIC Staff 5-10 inches is expected to fall through the daylight hours.
CNFAIC Weather Page and the NWS forecast
Chris will issue the next advisory Thursday 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.