Turnagain Pass Avalanche Forecast
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The avalanche danger is MODERATE above 1000′. Up to 3″ of snowfall and moderate winds today will create fresh wind slabs up to 2′ deep which are most likely to be found at upper elevations. Active weather will make natural avalanches possible in the afternoon and the avalanche danger will trend towards CONSIDERABLE in the alpine. In addition, persistent weak layers exist in the upper snowpack across the forecast area which could create wider propagating avalanches with the potential for remote triggering (being triggered from above, below, or to the sides of steeper terrain). The avalanche danger is LOW below 1000′.
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 |
After a few days of sunny skies we are heading back into a stormy weather pattern. A weak low pressure system is forecast to produce 4-8″ of snowfall over the next two days in coastal areas (Girdwood, Portage, Placer) and closer to 1-3″ of new snow in Turnagain Pass. Winds are also expected to increase into the 15-25 mph range out of the southeast and redistribute the surface snow into fresh wind slabs. The primary avalanche problem today will be wind slabs up to 2′ deep which will be most likely at upper elevations along ridgelines, cross loaded gullies, and convex roll overs. The 1-3″ of new snow expected today will add some loose snow at the surface for the winds to redistribute.
The visibility could make it challenging to travel in areas seeing the most wind loading today, but keep an eye out for active wind transport, shooting cracks, and hollow feeling snow to locate fresh wind slabs if you get into alpine terrain. An added complication is that we have a variety of persistent weak layers in the upper snowpack that could become more active from the new snow and wind loading (check out problem 2 for more details). We recommend evaluating the terrain and snowpack carefully and being aware of the potential for avalanches to be remote triggered if you are in an area harboring persistent weak layers.
Winds expected to be stronger along the coast and Turnagain Arm today. Photo 3.9.22
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 |
The upper snowpack is harboring a variety of different persistent weak layers which were created about a week ago before the last significant snowfall. The most prominent are buried surface hoar and near surface facets which have both been found about 1′ deep in the snowpack in a variety of locations throughout the forecast area. The distribution of these weak layers is variable and the only way to know if they exist where you are travelling is by digging into the snowpack. Luckily they are not buried very deeply right now so this is a pretty easy task, but as the new snow starts to pile up on top of them it will get harder to locate the weak layers and the potential size of avalanches they could produce will increase.
There have been several observations of avalanches that were remote triggered or the person who triggered them was not the first on the slope (examples in Lynx Creek, Eddies, Seattle Ridge). These are classic signs of persistent weak layers and should be a warning sign moving forward. These weak layers might become more capable of producing avalanches with a new snow load or simply by wind creating a firmer slab on top.
Buried surface hoar underneath a soft slab on Tincan, this could become a larger issue once the slab is more cohesive (see ob here). Photo Kit Barton 3.7.22
Yesterday: Mostly cloudy with temps in the mid to upper 30s at lower elevations and mid 20s at ridgetops. Winds were consistently in the 10-20 mph range with gusts between 20-30 mph. No significant new snow accumulation.
Today: Another storm system is moving into the area today with new snowfall totals of 1-3″ expected during the day. Snow totals should be on the higher end of that range in Girdwood, Portage, and Placer, with Turnagain Pass on the lower end. Snow line should be down to sea level today. Winds are forecast in the 15-25 mph range at upper elevations.
Tomorrow: More snowfall is expected overnight tonight and tomorrow, with storm totals from now to Thursday night between 1-3″ for Turnagain Pass and 4-8″ for Girdwood, Portage, and Placer. Snow line is expected to creep up to about 500′ tomorrow as the temperatures increase. Winds will increase slightly overnight, ranging from 20-30 mph at upper elevations.
PRECIPITATION 24-hour data (6am – 6am)
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
---|---|---|---|---|
Center Ridge (1880′) | 34 | 1 | 0.1 | 94 |
Summit Lake (1400′) | 32 | 0 | 0 | 40 |
Alyeska Mid (1700′) | 32 | 1 | 0.1 | NA |
RIDGETOP 24-hour data (6am – 6am)
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
---|---|---|---|---|
Sunburst (3812′) | 20 | ENE | 15 | 37 |
Seattle Ridge (2400′) | 26 | SE | 13 | 25 |
Date | Region | Location | Observer |
---|---|---|---|
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.