Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Monday, January 16th 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).
There is a MODERATE avalanche danger today for small fresh wind slab avalanches on steep slopes above treeline. The winds are forecast to increase slightly in the Turnagain Pass area but have spiked overnight south of the Pass in the Summit Lake region. Watch for recent, or ongoing, wind loading in these areas. There is also a continued MODERATE danger in steep terrain for easily triggered sluffs. Areas without wind below treeline will have a generally LOW danger.
Yesterday, widespread, yet manageable, avalanche activity was seen and reported. Sluffing in areas with 4-10″ of loose snow, which mainly sits on a hard wind slab, was the most prominent action. These were running easily on steeper slopes. In addition, some small fresh wind pockets, from the 10-20mph winds, had developed near the ridgelines and sub-ridges. Wind damage and hard surfaces are prevalent in many areas as well, especially at the upper elevations. Riding conditions have been, as one person put it: “blower to boiler plate”.
Today, the main concern will be associated with the recent, and forecast, increase in wind. Ridgeline winds have seen a spike in the Summit Lake area (gusts to 40mph) and steady winds in Turnagain and the Girdwood Valley are gusting near 20mph but forecast to increase to around 30mph later this morning. The increase is only 10mph or so, but from observations yesterday, I believe this is enough to form small wind slabs off the ridgelines and sub-ridges. Areas with loose snow will have plenty “AST” (Available Snow for Transport) to form soft sensitive pockets. These wind loaded areas are likely to be small and manageable but good to keep in mind; especially in committing terrain where getting pushed around can have higher consequences.
Additionally, human triggered sluffs will again be likely in the loose snow that sees minimal wind effect. The cold temperatures should keep the surface snow loose and easy to push down the steeper slopes, however, these should become smaller with time.
Yesterday a few high clouds were present but these have moved out and sunny skies are in store today. Overnight, temperatures dropped to the negative single digits at sea level and are sitting between 5 and 10 degrees above zero near 3000′. Temperatures should increase to around, or just above, 0F in the lower and mid elevations again today. Winds have been moderate gusting to 20mph on the ridgelines and are expected to increase slightly today with gusts around 30mph on the ridges.
The clear and cold weather will persist over our area. A strong high pressure has settled in over Alaska and is allowing for cold arctic air to move south. From the NWS’s 5am Discussion: “THIS WILL KEEP COLD NORTHERLY WINDS AND DRY CONDITIONS ACROSS THE MAINLAND FOR THE FORESEEABLE FUTURE…AND MAY EVEN USHER IN WAVES OF EVEN COLDER AIR BY NEXT WEEKEND”. Burr…
CNFAIC Weather Page and the NWS forecast
Again – We would like send a HUGE thank you to everyone who has submitted observations this weekend. They have been vital. Keep ’em coming!!
Graham will issue the next advisory Tuesday 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.