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The avalanche danger is MODERATE on all slopes above 2,000′ in elevation, where triggering a slab avalanche, breaking 1-3′ deep on a weak layer of snow is possible. Slabs may release after several tracks are on the slope and avalanches may be triggered remotely. Additionally, triggering a larger slab breaking near the ground remains possible at elevations above 3,000′.
The danger is LOW near 2,000′ and below.
Travel Advice | Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. | Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. | Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. | Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. | Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain. |
Likelihood of Avalanches | Natural and human-triggered avalanches unlikely. | Natural avalanches unlikely; human-triggered avalanches possible. | Natural avalanches possible; human-triggered avalanches likely. | Natural avalanches likely; human-triggered avalanches very likely. | Natural and human-triggered avalanches certain. |
Avalanche Size and Distribution | Small avalanches in isolated areas or extreme terrain. | Small avalanches in specific areas; or large avalanches in isolated areas. | Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. | Large avalanches in many areas; or very large avalanches in specific areas. | Very large avalanches in many areas. |
Signal Word | Size (D scale) | Simple Descriptor |
Small | 1 | Unlikely to bury a person |
Large | 2 | Can bury a person |
Very Large | 3 | Can destroy a house |
Historic | 4 & 5 | Can destroy part or all of a village |
Above ~2,000′ our concern is the New Year’s storm snow that has now settled into a slab, around 12 – 20″ at Turnagain Pass and 20-30″ in the Girdwood Valley. We have the buried surface hoar that was the cause for last week’s avalanche activity that sits right under this New Year’s snow. Could this slab/weak layer combination be triggered by the weight of a skier or snowmachiner? The answer is still YES. The buried surface hoar layer is slowly gaining strength and the slab is becoming more stubborn to trigger. However, snow pit results are still showing this layer to be reactive and to propagate – meaning human triggered slabs are possible if one hits the wrong spot on the slope. In addition, we are also concerned about slopes that avalanched in early December which have a thinner snowpack and harbor facets under the slab. Observers yesterday dug in a thinner spot on Sunburst and found reactive facets near the ground.
On January 2nd it rained up to 2,000-2,300′, creating melt-freeze crusts in the upper snowpack at these elevations and below, making triggering an avalanche unlikely in lower elevation terrain.
For those riders and skiers headed out today:
Wendy’s video and photo from 3,000′ on Sunday illustrate our current buried surface hoar issue well:
Thin snowpack at 3400′ on Sunburst. Note the weak faceted snow at the base under the slab. Photo: Sam Galoob
Signal Word | Size (D scale) | Simple Descriptor |
Small | 1 | Unlikely to bury a person |
Large | 2 | Can bury a person |
Very Large | 3 | Can destroy a house |
Historic | 4 & 5 | Can destroy part or all of a village |
Still reading… Deep Persistent Slabs have been in the forecast every day starting December 14th. Unfortunately it is a concern that we can’t ignore. At high elevations above 3,000’, human triggered large and dangerous deep slab avalanches are still possible. Weak sugary snow (basal facets) near the ground is creating a low probability/high consequence avalanche problem that is impossible to outsmart and will take a long time to heal. A big trigger like a snowmachine, more than one skier on the slope at the same time or a slab avalanche in the upper layers of the snowpack may be enough force to initiate a deep slab avalanche. Likely trigger spots will be in thinner areas of the snowpack that are connected to large, loaded slopes. Cautious route-finding is essential. This includes thinking about the remote trigger potential from below.
Yesterday was mostly clear and sunny above the valley fog. Temperatures were in the low 20Fs at upper elevations and in the teens to single digits in the valley bottoms. Winds were mostly light and variable.
Today there will be patchy valley fog in the morning but that should dissipate as cold dry air pushes into the region. Winds will be northerly 5-15 mph with gusts into the 20s. Temperatures will be in the low 20s and high teens today, dropping into the low teens and single digits tonight.
Tomorrow will be partly cloudy with a chance of snow showers in the afternoon and temperatures in the high teens and low 20Fs. Winds will be from the SE 10-20mph. The weather looks to be unsettled into the weekend with snow showers and warming temperatures. Stay tuned!
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
Center Ridge (1880′) | 24 | 0 | 0 | 43 |
Summit Lake (1400′) | 6 | 0 | 0 | 15 |
Alyeska Mid (1700′) | 18 | 0 | 0 | 36 |
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
Sunburst (3812′) | 22 | variable | 4 | 15 |
Seattle Ridge (2400′) | 21 | S | 10 | 23 |
Date | Region | Location | Observer |
---|---|---|---|
03/27/24 | Turnagain | Observation: Tincan Trees | A S Forecaster |
03/26/24 | Turnagain | Observation: Cornbiscuit | Krueger/ Sykes Forecaster |
03/25/24 | Turnagain | Observation: Tincan | Jack Peabody |
03/22/24 | Turnagain | Avalanche: Magnum Northwest Aspect | Aubrey Palmer |
03/21/24 | Turnagain | Observation: Sunburst | John Sykes Forecaster |
03/21/24 | Turnagain | Observation: Tincan Proper North Aspect | Shasta Hood |
03/20/24 | Turnagain | Avalanche: Seattle Creek Drainage | Wagner / Keeler Forecaster |
03/19/24 | Turnagain | Observation: Tincan CFR | N. Dumont B. Matthys |
03/18/24 | Turnagain | Avalanche: Tincan – Eddies – Seattle Ridge | CNFAC Staff |
03/18/24 | Turnagain | Observation: Tincan | jim sweeney |
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