It has been four days since the temperatures began cooling off and the extended wet storm cycles ended. It has been two days since the last snowfall. We are slowly getting a handle on the stability of the snowpack and a big thank you to all the folks that wrote in last night. We are most concerned with a known layer of faceted snow near and/or on the ground. This layer produced widespread human and natural avalanche activity during the beginning of December. The wet storms saturated the pack (and many of the facets) from 2,500′ in elevation and below, which is now locked up into stable crusts. From 2,500′ – ~3,000′ the facets remain but several thick crusts in the slab are helping to stabilize the pack. The big question is, above 3,000′ where the crusts disappear and facets under a hard slab may remain. Stability tests so far have been done up to 3,300′ and all signs point to a strong snowpack and no reactivity in the facets. See video below. This is promising. But, we must be vigilant and conservative this week as we explore the higher elevations.
Things to keep in mind:
– Triggering a dangerous deep slab avalanche is possible above 3,000′
– Shallow snowpack areas are most concerning (more trigger points and possibly more reactive facets). For instance, South end of Turnagain Pass, Crow Pass, Summit Lake
– No red flags likely to be present to indicate an unstable pack
Pictured below is the North side of Magnum Ridge showing wind scouring and a thin snowpack. The top portion pokes into the elevation band we are concerned about.
The other set of avalanches problems we are still assessing are old wind slabs, cornices and sluffing. These are surface instabilities and much easier to see and assess. So far we have found good bonding with Friday’s new snow as wind slabs seem quite stubborn. However, we have only had information for a small amount of terrain. Keep an eye out for cracking in the snow around you, hollow feeling snow and stiff snow over softer snow. In most places under 2,500′ there is crust underneath, watch for area where the Friday’s snow is not bonding to this crust.
The SW face of Sunburst. Old avalanche debris is covered by 8″ or so of new snow from Friday, Dec 15th.
Partly cloudy skies were over the forecast area yesterday. During the past 48-hours there has been no precipitation. During the past 24-hours winds have been light from the East and North and temperatures in the mid 20’s at most locations. Overnight, an inversion has set in and valley bottoms are in the low teens while ridgelines are in the upper teens.
Today, we can expect a mostly sunny day. Ridgetop winds are forecast to remain light, 5-10mph from a Northerly direction and switch to Easterly tonight, remaining light. Temperatures in valley bottoms should climb during the day to the mid 20’sF while ridgetops remain in the low teens.
Tuesday, another round of snow is headed our way as a bearing low pushes a front over Southcentral. This system looks to be cold enough for snow close to sea level, it also should favor Anchorage, Hatcher Pass and bring a several inch refresh to our neighborhood in Turnagain Pass. Make sure and check tomorrow’s advisory!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||24||0||0||33|
|Summit Lake (1400′)||25||0||0||27|
|Alyeska Mid (1700′)||18||0||0||10|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||22||SE||4||8|
|04/21/21||Turnagain||Observation: Sunburst||Schauer/ Behney Forecaster|
|04/19/21||Turnagain||Avalanche: Triangle, Seattle creek||Will Morrison|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|04/18/21||Turnagain||Observation: Seattle Ridge, approximately 300 yards south of the up track||Brent Byrne|
|04/17/21||Turnagain||Avalanche: Road obs||Johnston-Bloom / Moderow Forecaster|
|04/16/21||Turnagain||Avalanche: Seattle Ridge||Wendy Wagner Forecaster|
|04/16/21||Turnagain||Avalanche: Turnagain Pass, non-motorized side seen from Seattle Ridge||CNFAIC Staff Forecaster|
|04/16/21||Turnagain||Observation: Sunburst||Lance breeding|
|04/15/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|04/13/21||Turnagain||Observation: Turnagain Pass Road Obs||A Schauer 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: email@example.com
|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.