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ARCHIVED - Forecasts expire after 24 hours.
Issued
Sun, January 28th, 2024 - 7:00AM
Expires
Mon, January 29th, 2024 - 7:00AM
Forecaster
Andrew Schauer
Avalanche risk The Bottom Line

The danger remains MODERATE above 1000′. A storm is heading our way starting this afternoon, but with most of the snow expected to arrive after sunset, we do not expect avalanche danger to rise until tonight. Our main concern for now remains the active glide cycle that we have been seeing for over a month now. These avalanches are large and unpredictable, so avoid spending any time under open glide cracks if at all possible. Be on the lookout for increasing avalanche danger when the snow picks up, and be prepared to adjust travel plans if the weather arrives early. The danger will remain LOW below 1000′ until the snow gets here.

Special Announcements

The National Weather Service has issued a Winter Storm Warning for the approaching storm.

POSTPONED! The Avalanche Rescue Skills Workshop at the Glen Alps trailhead has been rescheduled to February 3. The event is hosted by the Anchorage Nordic Ski Patrol and Friends of Chugach Avy.

SnowBall 2024:  Mark your calendars for Valentine’s Day, Feb 14 (7-11pm @ 49th St Brewing). Details and tickets HERE. The evening promises costumes, finger food, a rocking band, silent auction, and of course plenty of great company. Join us in supporting Chugach Avy as well as our friends at the Alaska Avalanche School.

Sun, January 28th, 2024
Alpine
Above 2,500'
2 - Moderate
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
Avalanche risk
Mon, January 29th, 2024
Alpine
Above 2,500'
3 - Considerable
Avalanche risk
Treeline
1,000'-2,500'
3 - Considerable
Avalanche risk
Below Treeline
Below 1,000'
3 - Considerable
Avalanche risk
Mon, January 29th, 2024
Alpine
Above 2,500'
3 - Considerable
Avalanche risk
Treeline
1,000'-2,500'
3 - Considerable
Avalanche risk
Below Treeline
Below 1,000'
3 - Considerable
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
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.
Recent Avalanches

The latest avalanche in the ongoing glide cycle happened Friday night, when a large glide avalanche released directly above the motorized uptrack on the front side of Seattle Ridge. The avalanche put a massive debris pile on the main part of the uptrack.

This glide avalanche from Friday night was the most recent avalanche to hit the common uptrack on the front side of Seattle Ridge. This one did the most damage, putting a significant amount of debris on the middle portion of the uptrack. 01.27.2024

Avalanche Problem 1
  • Glide Avalanches
    Glide Avalanches
  • Aspect/Elevation
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Glide Avalanches
Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.

Aspect/Elevation of the Avalanche Problem
Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.

Likelihood of Avalanches
Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.

Size of Avalanches
Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

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
More info at Avalanche.org

After 21 days without a major precipitation event, we are expecting to see a change in the weather starting this afternoon. Although we may see a foot or more snow by mid day tomorrow, it is looking like most of that will arrive after sunset today which means for now the avalanche conditions should remain similar to what they have been for most of the month. Our main concern remains the active glide cycle that we have been watching unfold since late December.

We have seen unusually active glide conditions from Girdwood all the way to Seward, with a lot of activity concentrated in high-use areas. The most recent glide avalanches were early Thursday morning and early Friday night, with two avalanches that left a large amount of debris on the main uptrack on the front side of Seattle Ridge. In addition to the incredible amount of glide activity on Seattle Ridge, we have also seen widespread activity on virtually every ridgeline on the skier’s side of the pass, as well as significant activity in the Girdwood and Summit areas (check out the photos in this observation from yesterday for a sense of the extent of the current state of glide activity in Turnagain Pass). Glide avalanches are different from most other avalanches in that we have no way of predicting the timing of their release. On the other hand, since most glide avalanches occur after a glide crack has opened up we have a much better idea of exactly which slopes are most vulnerable. The best way to manage this avalanche problem is to avoid traveling on or below slopes with open glide cracks. If you can’t find an alternate route, you can reduce your exposure by traveling quickly one at a time under glide cracks and watching your partners from safe areas outside of avalanche runout zones.

Keep the approaching storm in the back of your mind today, and expect to see increasing avalanche danger if the weather arrives sooner than expected. We know this new snow will be falling on weak surfaces, and we are expecting avalanche conditions to be dangerous once the snow starts accumulating. Hopefully we will end up on the high end of the snow forecast, we’re all looking for a good reset!

 

Closer view of the two recent glide avalanches on the front side of Seattle Ridge. The avalanche on the left occurred early Thursday morning, while the one on the right occurred early Friday night. 01.27.2024

While the bulk of this storm is expected to hit areas east of us, we could see a foot or more of snow in some portions of our advisory area by tomorrow afternoon. Graphic courtesy of NWS Anchorage. 01.28.2024

 

Weather
Sun, January 28th, 2024

Yesterday: Temperatures stayed cold yesterday as an arctic air mass continues to push into our region, with highs in the single digits above and below 0 F and lows in the single digits to teens below 0 F. Skies were partly to mostly cloudy, with light winds out of the north. Some areas got 1-3 inches of very low density snow, which at some stations did not even have enough water weight to register on the sensors.

Today: After three weeks without a significant precipitation event, we are looking at a pattern change today. Although the brunt of this storm is expected to impact areas east of our advisory area, we may still see a foot or more of snow by the time the storm passes tomorrow afternoon. For today, expect to see 1-3” snow this afternoon with winds staying light and variable for most of the advisory area. Temperatures should start rising this morning, getting up to the single digits to low teens F by sunset, and continuing to warm up to the high teens to high 20s F tonight. Skies should be partly to mostly cloudy, and we are expecting to see snow to sea level for this event.

Tomorrow: The most intense stormy period is looking to be tonight into tomorrow morning. Girdwood and Turnagain Pass may see 10-14” snow, with 18-24” possible in Portage and Placer. Summit and Seward are looking to receive less snow, with around 4-8” expected. Winds should remain reasonable at around 10 mph out of the east with gusts of 15-20 mph. High temperatures will be in the 20s F with lows dropping back down to the single digits to mid teens F.

PRECIPITATION 24-hour data (6am – 6am)

Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) -4 1 tr 77
Summit Lake (1400′) -12 0 0 N/A
Alyeska Mid (1700′) -2 3 0.03 76
Bear Valley – Portage (132′) 6 3 0.17
Grouse Ck – Seward (700′) 1 0 0 50

RIDGETOP 24-hour data (6am – 6am)

Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) -3 W 5 12
Seattle Ridge (2400′) -8 4 9 NNE
Observations
Recent Observations for Turnagain Pass
Date Region Location
02/24/24 Turnagain Observation: TinCan Backdoor/ Center Ridge
02/22/24 Turnagain Avalanche: Lynx Creek
02/22/24 Turnagain Observation: Turnagain, Seattle, Mt Ascension
02/21/24 Turnagain Observation: Tincan Trees
02/21/24 Turnagain Observation: Sunburst
02/20/24 Turnagain Avalanche: Tincan
02/20/24 Turnagain Observation: Seward Highway across from Johnson Pass TH
02/19/24 Turnagain Avalanche: Base of Seattle Ridge
02/18/24 Turnagain Observation: Lynx creek
02/18/24 Turnagain Observation: Tincan Trees
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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.