Yesterday 3-5″ inches of snow fell at upper elevations and winds were southeasterly, 15-25 mph gusting into the 30s. Winds shifted to the west in the evening. Observers reported pockets of reactive wind affected snow in leeward terrain. Today wind slabs are possible on steep wind loaded slopes. Look for drifting, cracking and pay attention to stiff snow under foot. Even a small wind slab can be very dangerous in high consequence terrain. In addition, give cornices a wide berth. They have been growing with each new snow and loading event.
Cornices building and the leeward slopes of Hippy Bowl on Tincan. Photo: Sam Galoob, December 16th.
It has now been a week since the widespread natural avalanche cycle that was initiated by the warm wet storms ended. We have had no reports of human triggered avalanches since December 6th. We still do not have much snowpack data from above 3,300′ this season. What we do know is that the snowpack depth is variable and that there were large natural avalanches in upper elevation terrain during the storms in the first two weeks of December. The concern is that on slopes that did not slide in the Alpine, there is still weak snow underneath all that storm snow and that a deep slab avalanche could be triggered if you found the wrong spot. If you venture out into the higher elevations today there are a few things to keep in mind:
– Triggering a dangerous deep slab avalanche is still possible above 3,000′
– Shallow snowpack areas are most concerning (more trigger points and possibly more reactive facets). For example: the South end of Turnagain Pass, Crow Pass and Summit Lake
– No red flags are likely to be present to indicate an unstable snowpack. It might not be the first person on the slope that triggers the avalanche. It could be the 10th. That is why deep slabs are so spooky.
The bottom line is that we need more data on the snowpack structure above 3500′ to rule out deep slab avalanches. This picture shows the basal structure we are concerned may still be lurking under feet of snow at upper elevations.
Yesterday was cloudy and there were snow showers on and off throughout the day. 3-5″ fell at upper elevations. There was brief sleet/drizzle later in the day below 500′. Winds were easterly during the day and shifted to the west in the evening. Wind speeds averaged 15-25 mph and gusted into the 30s. Temperatures were in the low 30Fs at sea level and the low 20Fs at ridge-tops.
Today is will be partly sunny with a slight chance of snow showers in the am. Westerly winds will be light. Temperatures will cool into the low 20Fs today and dip into the teens tonight.
Tomorrow will be sunny with temperatures in the low 20Fs and light southerly winds increasing in the late afternoon. Friday will be mostly cloudy with a chance of snow showers. The next storm system looks to impact the area over the weekend. There is some hope that it won’t be too warm but there is still some uncertainty. Here are the last few sentences of the NWS discussion this morning; “Behind this low is some significant cold air, which brings a chance for snow for all portions of the forecast area before Christmas Day. Either way, the forecast looks to be messy for the weekend before a return to more seasonable weather early next week.” Let it snow, let it snow, let it snow!
* Sunburst weather station is down due to loss of battery power.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||27||0||0||32|
|Summit Lake (1400′)||27||3||.3||12|
|Alyeska Mid (1700′)||28||3||.3||29|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||22||SE-W||16||37|
|05/06/20||Turnagain||Avalanche: Pastoral Peak, north face||Andy Duenow|
|04/10/20||Turnagain||Avalanche: Wolverine||Mike Records|
|04/10/20||Turnagain||Observation: Eddies lookers right shoulder||Matt Yoder|
|04/09/20||Turnagain||Observation: Bench Peak||Mike Records|
|04/04/20||Turnagain||Observation: Pete’s North||Anonymous|
|03/26/20||Turnagain||Avalanche: Tincan – Proper (SW facing)||CNFAIC Staff|
|03/26/20||Turnagain||Avalanche: Seattle Ridge||W Wagner Forecaster|
|03/25/20||Turnagain||Avalanche: Sunburst Uptrack @ 2000′||J. Boisvert|
|03/24/20||Turnagain||Observation: Turnagain – Road Observations||W Wagner Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: firstname.lastname@example.org
|Area||Status||Weather & Riding Conditions|
This is 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.