Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Thursday, February 23rd 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).
Pockets of MODERATE avalanche danger exist on the steep slopes above treeline for human triggered sluffs, possible cornice breaks and lingering wind slabs. CNFAIC Staffwise, there is a generally LOW avalanche danger. LOW does not mean NO danger and one’s guard should always stay up, especially on any steep rollover or slope. On the outskirts of the core Turnagain Pass zone, including the Summit area, where the winds did not die down as much yesterday, expect a generally MODERATE danger.
Springtime is knocking at the door. The cold snow that fell Monday into Tuesday was moistened with the sun yesterday and many rollerballs, along with some point release wet snow avalanches, were seen on southerly aspects. By late afternoon, a thin sun crust had formed in some, but not all, areas on the southern half of the compass. CNFAIC Staff avalanche activity yesterday included human triggered dry sluffs which were relegated to the steeper slopes. Additionally, there was one report of a few small slabs that released sometime in the past couple days in the Johnson Pass area. These were thought to be triggered by naturally occurring sluffs initiating in the rocks above.
Over the past week we have been poking and prodding as much as possible at the snowpack hunting for the more dangerous slab avalanche. During the last storm on Monday (2/20) several large cornices fell naturally (check out this great observation from the Seattle Creek region). Furthermore, my party yesterday triggered a limousine size cornice onto a steep 38-40 degree slope. These natural ‘bombs’, or ‘triggers’, did not produce avalanches. The pack is generally, as many professionals in the area call, ‘right side up’ and Kevin demonstrates that in his video from Tuesday.
That being said, there still remain avalanche concerns for today:
Loose snow sluffs are likely to be easy to initiate again in the steep more radical terrain. Sluff management will be required as these can entrain a lot of snow, especially if they funnel into a gully. In areas where the sun did not hit the cold snow yesterday, and peaks out enough to do so today, wet loose sluffs will be possible.
Cornice breaks are a legitimate concern for anyone traveling on ridgelines. These have grown substantially over the past three weeks and though they are not likely to release on their own today, are still possible to trigger by the weight of snowmachine or person/people. Cornices should be given a wide berth and can be very dangerous.
Lingering wind slabs are still possible to be found in isolated steep and exposed areas. Especially where the slope is unsupported from below (e.g., slopes that have cliffs below).
It was a fairly calm day in the mountains yesterday with clouds filtering in and out and a few snow flurries adding a trace of snow to Turnagain Pass. Westerly winds were light with a few gusts to 20mph at the Sunburst weather station. Temperatures warmed up from the high teens to the upper 20’s at 2000′ while upper elevations stayed in the mid-teens.
Today, anCNFAIC Staff calm day with intermittent snow flurries is on tap. Overnight, winds have shifted around from the west to an easterly direction and decreased to 5mph where they are forecast to remain. Clouds should be in and out again with anCNFAIC Staff trace to an inch of snow expected. Temperatures are currently in the mid to upper teens at most stations and should increase into the mid 20’s at treeline and below while upper elevations will remain in the teens.
CNFAIC Weather Page and the NWS forecast
Kevin will issue the next advisory Friday 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.