Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, February 19th 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).
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Remember, we now have a Sunday Summit Lake forecast issued by our awesome intern, Adam Clark.
There are pockets of CONSIDERABLE danger today on steep, wind loaded slopes for triggering a wind slab avalanche. These are most likely to be found above treeline and in areas where winds will be depositing 1-4″ of new snow as well as older snow. CNFAIC Staffwise, there is a generally MODERATE avalanche danger where it may be possible to trigger an avalanche in the older storm snow in areas the snowpack has not yet adjusted to the significant load from the recent storm cycles.
We did not hear of, or see, any avalanche activity yesterday. Low visibility, light snow showers and moderate winds above treeline kept most folks recreating in the treed areas, which did sport the best riding conditions as well. The few inches of new snow that did fall, was easily blown around above treeline where the surface conditions have varying degrees of wind effect. This will likely be the case again today with anCNFAIC Staff few inches of snow forecast.
Wind slab avalanches continue to be the primary concern. Winds are forecast to increase into the moderate category (17-25mph averages) which is enough for transporting and depositing snow into slabs. Watch for these to form on the leeward sides of ridgelines, over the tops of rollovers and cross-loading in gullies. Keep an eye out for the snow to ‘talk’ to you by collapsing and/or cracking around your snowmachine, board or skis. These are bull’s eye clues the slope could slide.
Overall, signs continue to point to a snowpack that is adjusting very well to the more than 100″ of snow added to it during the past 2 1/2 weeks of stormy weather. A bit of slope stability analysis at 3500′ yesterday lent itself to very favorable results. This was the first time we really were able to take a good look at the upper elevation pack. Today will be our third day since the last bona fide system rolled through on Thursday and our last avalanche activity as well. Continued conservative travel is warranted as many unknowns still exist concerning the pack above treeline and in the more remote areas of our forecast zones.
Yesterday brought a bit of blow and 1-3″ inches of snow to Turnagain Pass and the Girdwood Valley, with only a trace in the Summit area. Winds were easterly averaging in the low 20’s with gusts near 40mph. Temperatures at sea level were in the low 30’s and in the mid-teens on the peaks. Overnight temperatures have begun a slight increase with southeast winds slowing down – averaging around 10mph with gusts to 20mph.
Today, a weak storm system moves through and weather should be somewhat similar to yesterday. Cloudy skies with light snow showers should add 1-4 inches and the southeast ridgetop winds are forecast to increase this morning to the 20mph range with gusts in the 40’s. Temperatures will hover around the low to mid 30’s at sea level and the upper teens to 20F on the peaks.
CNFAIC Weather Page and the NWS forecast
I will issue the next advisory Monday 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.