Good morning this is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, November 27th 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).
The avalanche danger is MODERATE for fresh wind slab avalanches on leeward slopes. Human triggered avalanches will be possible today in areas with recent wind deposited snow. These are most likely to be found above treeline, off ridgelines and on rollovers. Below treeline, and out of the wind, the danger is generally LOW.
Yesterday, 3 human triggered avalanches were reported in the Turnagain Pass area, both on the east and west side of the road. Details are limited, but it seems these were all confined to the new snow that has accumulated to 8-12+” during the past week.
Today, the primary concern will be fresh wind slabs forming due to the recent increase in wind. Though winds are moderate, currently in the 20’s, and expected to increase slightly into the 30’s, there is ample light snow to be blown around. Soft, sensitive wind pockets could be triggered in steeper leeward terrain today. Watch for any cracking in the snow from your sled, board or skis. This is a bull’s eye clue that a slab could pop and the slope could slide. Areas most likely to trigger a wind slab are on and off ridgelines and on the steepest point of a rollover/convexity.
To date, our snowpack has been relatively stable; however, it does have a poor structure. In general, there exists weak faceted snow sitting under a wind slab, varying from 0-12+” thick, with 8-12” of loose, new snow on top. With additional weight from new snow, or wind deposited snow, the weak faceted layer has potential to fail. In this case, larger and more unmanageable slides are possible. We are keeping this in mind as the winds pick up today and significant snowfall is expected this week.
Mid-level clouds yesterday allowed for sunny skies above treeline and cloudy skies below. Temperatures were around 10F while winds were light and variable. Overnight, winds picked up from the east and are currently gusting around 20mph. Today, patches of clear sky will begin to fill in with high clouds and light snow showers as a system moves in from the east. There is a chance for a few inches to fall by the evening, with several more accumulating into Monday. Winds are forecast to increase, gusting into the 30’s from the east, and temperatures will increase as well, rising into the mid and upper-teens today.
It looks as though a change in our colder than average weather pattern is approaching. Early next week, a large low pressure system is forecast to head into the Gulf, bringing warmer and wetter conditions.
CNFAIC Weather Page and the NWS forecast
I will issue the next advisory tomorrow morning at 7am. 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.