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 expected to rise to HIGH at all elevations by this evening. Heavy snowfall and strong winds impacting the mountains through today and into tonight will create dangerous avalanche conditions. Natural avalanches are likely to occur and human triggered avalanches will be very likely. Travel in avalanche terrain is NOT recommended.
A Winter Weather Advisory has been issued by the National Weather Service for Turnagain Pass and Portage Valley.
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 |
Finally, after an 11 day stretch of benign weather a storm is headed into the region. Ridgetop winds began picking up around 4am and snowfall should begin around 6am. The avalanche danger will rise through the day relative to the amount of new snow and wind. Turnagain Pass could see up to 18″ of snow by 6pm. Other areas could see more or less depending on where the storm favors. Ridgetop winds however should be widespread through the region blowing 45-55mph with gusts into the 70’s and 80’s mph.
If the storm verifies, we can expect a variety of storm snow avalanches to start occurring through the day. The first is storm slabs that form on slopes out of the wind. These are composed of the new snow and release when the new snow hasn’t bonded yet with the older snow surface. Second are wind slabs that develop on wind loaded slopes. These could be up to 2′ deep due to the strength of the winds. Third are loose snow avalanches that are common during storms in steep terrain. And last are fresh cornices. Chunks of cornices are likely to break off and could trigger avalanches below. Hence, we are expecting a HIGH avalanche danger by sunset.
For those headed out today, paying close attention to the changing weather will be key. Areas seeing less snowfall could still be quite dangerous due to the strong winds. If you are getting out early, know the danger will be rising rapidly. This new snow should be very light and with snow falling all the way to sea level, avalanches could be seen even in the lower elevations. Additionally, powder clouds and debris could run further than expected.
A quote from our friends at the National Weather Service this morning:
“There is quite a bit of uncertainty in snow amounts in the Portage and Turnagain Pass areas, where high snow ratios could bring up to 2 ft for Turnagain Pass and 3 ft for Portage Valley of snow through Monday morning.”
Snowfall amounts from 6am this morning through 6am Monday. Graphic by the NWS that can be found on their Avalanche Weather Guidance page HERE.
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 |
Today’s new snow and wind will be a good test for the layer of buried surface hoar that we’ve been worried about for the last two weeks. This layer was 2-3′ deep but should be 3-4′ deep after today. After being very reactive 2 weeks ago, it was healing and not showing signs of reactivity the past several days. We will be trying to assess if any storm snow avalanches will step down and cause this layer to fail. If that happens, a much larger avalanche would result.
We are still tracking the Thanksgiving facet/crust combo at the base of the snowpack. Even with 1-1.5″ of water weight with today’s storm, it’s unlikely this is enough load to reactivate this very deep layer. This is something we are watching for in the future if we get into a more potent storm series.
Yesterday: Partly cloudy to sunny skies were over the region with light southeasterly winds along the ridgetops. Temperatures were in the teens at the higher elevations and in the 20’s at the lower elevations.
Today: A storm is heading in today bringing strong easterly winds and snowfall. The peak of the storm should be this afternoon. Between 1-2′ of snow is expected. Ridgetop winds should pick up to 45-55mph with stronger gusts by midday. Temperatures will remain just cool enough for snow to fall to sea level.
Tomorrow: As the storm moves out tomorrow, light snow showers could add another 2-6″ to the storm total. Ridgetop winds shift more southerly and decrease to the 20-30mph range. Temperatures are forecast to rise slightly, creating some light rain at sea level.
PRECIPITATION 24-hour data (6am – 6am)
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
---|---|---|---|---|
Center Ridge (1880′) | N/A* | N/A* | N/A* | N/A* |
Summit Lake (1400′) | N/A* | N/A* | N/A* | N/A* |
Alyeska Mid (1700′) | 22 | trace | 0.05 | 64 |
Bear Valley – Portage (132′) | 25 | 2 | 0.2 | – |
*The Snotel server is down. No data.
RIDGETOP 24-hour data (6am – 6am)
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
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Sunburst (3812′) | 15 | NE | 5 | 26 |
Seattle Ridge (2400′) | 18 | SE | 2 | 21 |
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.