Turnagain Pass Avalanche Forecast
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High Avalanche Danger
Travel in avalanche terrain is not recommended. Avoid being on or beneath all steep slopes.
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The avalanche danger is HIGH as strong winds and heavy snowfall overload a weak snowpack. Large natural and human triggered avalanches 3-6′ deep or deeper are very likely today, and will run long distances into valley bottoms. Travel in avalanche terrain is NOT recommended. This includes flat terrain below steeper slopes.
*Roof Avalanches: Warm temperatures and heavy rain could cause roofs to shed the snow that has been stacking up for the past month. Pay attention to children and pets, and be mindful of where you park your vehicles.
PORTAGE/PLACER: These areas will see heavier snowfall than the Girdwood and Turnagain zones, with 1-2′ by tomorrow morning. Very large avalanches are likely.
SUMMIT LAKE: This will be the first major loading event on the weak snowpack in the Summit Lake area, creating the potential for large natural avalanche activity.
SNUG HARBOR/LOST LAKE/SEWARD: These zones are expected to see the heaviest snowfall during this storm, with over 2′ of snow expected by tomorrow morning.
There will be intermittent traffic delays Monday, December 6, 2021 on the Portage Glacier Road for Avalanche Hazard Reduction work. Motorists should expect delays of up to 45 minutes to 1 hour between 11 AM and 12:00 PM. More info at https://511.alaska.gov/
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 |
The much-anticipated storm arrives in force today, with strong winds and heavy snowfall expected through tonight. Some areas (Portage/Placer and Seward) may see 2-3′ of snow, while the core of the advisory area is going to be on the low side of storm totals, with only 4-8″ snow expected by tomorrow morning. We saw natural avalanches yesterday as winds were blowing 15-35 mph with gusts up to 68 mph. We can expect more today as snowfall picks up and winds increase to the 20-40 mph range, gusting 40-60 mph. This combination of new snow and strong wind will make sensitive slabs that fail naturally today, and are likely to step down to deeper weak layers in the snowpack, resulting in very large avalanches (more on this in problem 2 below). These avalanches are expected to run long distances into runout zones at lower elevations. Travel in and below avalanche terrain is not recommended today, including nordic and hiking trails that will be exposed to avalanche hazard from above.
Skiers saw sensitive conditions on Notch yesterday as winds picked up, with multiple shooting cracks and soft slabs releasing on small terrain features like the one pictured above. Photo: Kakiko Ramos Leon. 12.05.2021
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 |
Although this storm may be somewhat unremarkable on its own by Chugach standards, it will likely be the extra load needed to make very large avalanches on an already dangerous snowpack. Strong winds and new snow will add a lot of weight to a snowpack supported by multiple weak layers, likely pushing them to their breaking point. As we saw towards the end of last week, these weak layers were already capable of producing very large avalanches (take a look at this avalanche from Eddie’s or this one from Magnum for a reminder).
These weak layers have been propagating long distances, and people have been triggering avalanches remotely- from above, below, and to the side of steep slopes. With the added potential for natural triggers, avalanche conditions are very dangerous right now. Very large avalanches are expected to run into flat terrain below steeper slopes, which means users like hikers, bikers, and nordic skiers need to be aware of the overhead hazard. Long story short, today is really not the day to try to get out in the mountains.
Large natural avalanches like this one on the Karlsberg path on Orca from last week are on our mind today. Similar activity is expected as winds continue to load a dangerous snowpack.
As if we didn’t already have enough to worry about with wind slabs, storm slabs, and persistent weak layers, we are also still thinking about the potential for large glide avalanches. Glide avalanches are impossible to predict, but the rapid warm up over the past 24 hours is not likely to improve the glide condition.
Yesterday: Strong winds were blowing 15-35 mph, with gusts to 68 mph at Alyeska and up to 59 mph at the Sunburst station. Temperatures have climbed steadily from the mid 20’s yesterday morning to the low 30’s this morning. Snow started falling last night, with around 3-4″ snow at mid and upper elevations as of 6:00 this morning.
Today: Snow is expected to pick up today and continue through tonight. Totals will be around 3-5″ snow near Girdwood and Turnagain Pass during the day and 8″-12″ by tomorrow morning. Heavier snow is expected near Portage and Seward, with 1-2′ expected near Portage and 2-3′ near Seward. Temperatures are expected to hover in the mid 20’s to low 30’s F, with strong easterly winds blowing 20-40 mph and gusting 40-60 mph.
Tomorrow: We will see an abrupt pattern change tomorrow as the low pressure system exits to the east. Winds are expected to shift, blowing 15-25 mph from the northwest. Clouds will start to lift through the day, and temperatures will drop into the low teens to single digits F. Snow is expected to taper off early tomorrow morning.
PRECIPITATION 24-hour data (6am – 6am)
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
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Center Ridge (1880′) | 27 | 4 | 0.4 | 60 |
Summit Lake (1400′) | 21 | 3-4 | 0.3 | N/A |
Alyeska Mid (1700′) | 25 | 6 | 0.48 | 36 |
RIDGETOP 24-hour data (6am – 6am)
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
---|---|---|---|---|
Sunburst (3812′) | 17 | ENE | 23 | 59 |
Seattle Ridge (2400′) | 21 | SE | 15 | 28 |
Date | Region | Location | Observer |
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05/22/23 | Turnagain | Avalanche: Tincan | Nick D'Alessio |
05/12/23 | Turnagain | Avalanche: Tincan, Sunburst, Magnum, Cornbiscuit | Heather Thamm |
05/07/23 | Turnagain | Observation: Tincan – Bear Tracks | CNFAIC Staff |
05/05/23 | Turnagain | Observation: Seattle Ridge | AS/ WW Forecaster |
05/02/23 | Turnagain | Observation: Cornbiscuit | Schauer/ Sturgess Forecaster |
05/02/23 | Turnagain | Observation: Seward Hwy Turnagain Pass | Joel Curtis |
04/30/23 | Turnagain | Observation: Magnum | Ayla, Kit Crosby, Barton |
04/29/23 | Turnagain | Observation: Tincan | John Sykes |
04/28/23 | Turnagain | Avalanche: Taylor Pass/Pastoral | Schauer/ Creighton Forecaster |
04/28/23 | Turnagain | Avalanche: Tincan | Andy Moderow |
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: mailroom_r10_chugach@fs.fed.us
Area | Status | Weather & Riding Conditions |
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Glacier District |
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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.