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The avalanche danger is CONSIDERABLE on all aspects above 2,500′ due to strong east winds with several inches of new snow. Fresh wind slab avalanches in the 1-2′ deep range will be likely for people to trigger and may release naturally in the upper elevations. Winds may also build slabs below 2,500′ and a MODERATE danger exists where human triggered wind slabs are possible. Small wet sluffs could occur in the lower elevations as light rain on snow is likely this afternoon.
SUMMIT LAKE: Despite almost no new snow expected for the Summit Lake area, strong winds may be able to form new wind slabs and increase avalanche danger here as well. Avalanches could step down into buried weak layers, resulting in a much larger avalanche.
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 |
Well… we were hoping for a foot of new snow by today, but it appears we have to settle for half that, or less! As of 6am this morning, snowfall totals are 3-6″ in Girdwood Valley and only 1-3″ at Turnagain Pass. Weather models are showing only 1-3 additional inches to fall through the day with a rain/snow line rising to ~800′ by this afternoon. The easterly ridgetop winds however, are verifying. For the past 6-8 hours ridgetop stations have recorded 15-30mph averages and gusts into the 40’s and 50’s. That said, it’s a watch out for new wind slabs kind of day.
We can expect wind slabs to be forming predominantly in the Alpine, above 2,500′, and may be releasing naturally. How large they could be will depend on both the new snow amounts and how much soft pre-existing snow the winds will be able to move. The snow surface was a mixed bag before the storm; sun crusts on south aspects, stiffer wind crusts along ridgelines and soft settled snow on shaded slopes. Plus, all these surfaces were covered with a new batch of surface hoar. Hence, wind slabs could be anywhere from 6″ to 2′ thick. They could be quite touchy and easy to trigger as they are likely sitting on this new layer of surface hoar and possibly some loose near surface facets.
Taking stock of how much new snow has fallen along with active wind loading and areas with wind deposited snow will all be key. The classic red flags will also be useful in looking for unstable snow. These are any recent avalanches? Is the snow cracking around you and feel hollow? Any collapsing or whumpfing in the snow under you? All in all, we should steer clear of any wind loaded slope or cross-loaded gully. Exposed areas in the trees could also see some wind loading.
A new batch of surface hoar has been growing the past few days. It may have been blown over in many places before the snowfall, but it also may be standing up and not allowing the new snow to bond well. Photo by CNFAIC Intern Allen Dahl in Kern Creek around 2,600′ yesterday, 3.15.22.
Cornices: Pieces, parts of even large sections of cornices may break off with these winds and could trigger an avalanche below. This is just one more thing to watch for, and avoid being near, if venturing out today.
Small dry and wet sluffs: We can expect the new snow to sluff fairly easily on the older snow surface. With such meager new snow amounts, sluffs should be quite small. Dry sluffs are expected above ~1,000′ and wet sluffs below that due to rain/snow.
Glide cracks: Warming temperatures through today and into the weekend may accelerate the opening of glide cracks and even cause a couple to release into avalanches. There are several of these cracks scattered about. Limiting and/or avoiding any time under them is highly recommended as they can release at any time.
Glide crack underneath the steep rocky bands. This crack was reported to be slowly opening in the past few days. It is on the Girdwood side of Crow Pass in the Crow Creek drainage. 3.15.22.
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 |
Buried in the top 2 feet of the snowpack is an older layer of buried surface hoar and small facets. It was buried on March 2nd and was the cause of several avalanches over a week ago. The last known avalanche on this layer was last Saturday in the Bertha Ck drainage at Turnagain Pass. The layer has appeared to adjust and gain strength, but with a little new snow and especially wind loading, we are watching to see if any wind slab avalanches overload this layer and cause a larger slide today.
Yesterday: Mostly clear skies with valley fog was present yesterday morning before clouds move in midday. Ridgetop winds picked up from the E to SE midday (10-15mph) before climbing further overnight into the 20-30mph range with gusts into the 50’s. Overnight between 2-5″ of snow fell to sea level (Girdwood Valley saw the higher amounts).
Today: The storm that was hopefully going to add up to a foot of snow today has pushed to the east and we are expecting cloudy skies with only an additional 1-3″ by tonight. The rain/snow line looks to creep up to ~800′ by this afternoon. Ridgetop easterly winds should slowly lessen through the day from 20-30mph range (gusts to 50mph) this morning to 10-15mph (gusts to 30mph) by this evening.
Tomorrow: Continued cloudy skies with light to moderate precipitation should remain through tomorrow and into the weekend. Sea level elevations should see fluctuations of rain and snow while all snow should fall above 600-800′. Ridgetop winds will remain easterly in the moderate range (10-30mph).
PRECIPITATION 24-hour data (6am – 6am)
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
---|---|---|---|---|
Center Ridge (1880′) | 27 | 2 | 0.1 | 92 |
Summit Lake (1400′) | 20 | 0 | 0 | 39 |
Alyeska Mid (1700′) | 26 | 5 | 0.3 | N/A |
RIDGETOP 24-hour data (6am – 6am)
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
---|---|---|---|---|
Sunburst (3812′) | N/A* | N/A* | N/A* | N/A* |
Seattle Ridge (2400′) | 21 | SE | 14 | 26 |
*The sunburst weather station has lost power, we are working to get it back online as soon as possible.
Date | Region | Location | Observer |
---|---|---|---|
10/27/24 | Turnagain | Observation: Tincan | Michael Kerst |
10/21/24 | Turnagain | Observation: Turnagain Pass Road Observation | Trevor Clayton |
10/19/24 | Turnagain | Observation: Tincan – Below Todds Run | Andy Moderow |
10/18/24 | Turnagain | Observation: Taylor Pass | Eli Neuffer |
10/15/24 | Turnagain | Observation: Tincan Common | John Sykes Forecaster |
10/14/24 | Turnagain | Avalanche: Tincan | CNFAC Staff |
05/13/24 | Turnagain | Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South | H Thamm |
05/13/24 | Turnagain | Observation: Turnagain Pass non-motorized side | Amy Holman |
05/12/24 | Turnagain | Observation: Warm up Bowl | Tony Naciuk |
05/07/24 | Turnagain | Observation: Turnagain Pass Wet Slabs | A S |
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