Turnagain Pass Avalanche Forecast
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A storm bringing rain, snow and wind is expected to increase the avalanche danger to CONSIDERABLE through the day. Slab avalanches composed of up to a foot of new snow are likely to be triggered and may release naturally at the high elevations above 2,500′. Wet snow avalanches are likely to be triggered on steep slopes below 2,500′ where rain is falling on an already saturated and wet snowpack. Cornice falls are also likely along ridgelines.
Portage Valley hikers: Avalanche danger exists along popular hiking areas such as those accessed from Byron Glacier trail.
MONDAY AVALANCHE OUTLOOK:
No avalanche forecast will be issued tomorrow, Monday April 23rd. Pay close attention to warming on Monday and the possibility for triggering a slab avalanche in the Alpine and/or a wet loose avalanche at Treeline.
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 |
Another spring storm is impacting Western Prince William Sound. Heavy precipitation has been seen in the Portage Pass zone and along coastal areas, with moderate amounts of precipitation in Girdwood and Turnagain. The storm is expected to intensify today and bring another 6-12″ of snow to the Alpine and .5-1″ of rain to Treeline and below. The rain/snow line is around 1,500′ this morning and should climb to 2,500′ by this afternoon.
Estimated Storm Totals from yesterday through 6am today (Sunday):
Girdwood Valley: ~6-10+” snow above 2,500′
Portage Valley: ~16″ – 24″ snow above 2,500′ (twice as much precip seen in areas closest to the Sound compared to Turnagain/Girdwood)
Turnagain Pass: ~6-10″ snow above 2,500′
Summit Lake: 0″ to a trace
Some natural avalanche activity is expected today if the storm verifies due simply to ‘rapid loading’. In the Alpine there could be up to 2′ of snow in favored areas by this afternoon. In this case, storm slab and wind slab avalanches are likely to be triggered. Although bonding between the new and older snow surface should be relatively good, there is always a period of time needed for the new snow to stabilize. This could happen in several hours or 2 days. Quick hand pits are good ways to assess instability in the storm snow. Once again the avalanche danger will be directly related to the amount of new snow fallen. In areas seeing only 6″(ish) of new snow, slab avalanches are not expected.
Upper elevation North aspects: Shaded aspects in the Alpine had a thin layer of facets over a crust under last week’s new snow. This layer may still be lurking, which could result in slab avalanches 1-2+’ thick composed of last week’s new snow along with this weekend’s storm.
A brief period of sun yesterday at Turnagain Pass. New moist snow falling on a warm springtime surface should bond fairly quickly after the initial stabilization period. However, once it warms up – avalanche activity will be on the rise again.
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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 |
At the mid-elevations (below 2,500′) rain falling on a wet snowpack will keep the chances for natural wet loose avalanches possible on steep slopes. Make sure to avoid runout paths and gullies where even a small wet loose slide can send debris to valley floors. Triggering a wet avalanche will be likely if you find yourself on a steep slope with wet and unconsolidated snow.
Yesterday’s pre-storm snow surface and snowpack conditions at the mid-elevations. Rain at this elevation today will likely keep the snowpack punchy and wet, which means ripe for wet avalanches if the slopes are steep enough (greater than 35 degrees).
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Snow and wind continue to grow cornices along ridgelines. Cornice falls may trigger storm slab avalanches and/or wet loose avalanches today and looking ahead into the next several days of precipitation and warm temperatures. Give these a wide berth from above and limit exposure under them.
Mostly cloudy skies were over the region yesterday as another low-pressure system moved in. Light snow began to fall in the afternoon above 1,000′ and light rain below, the exception being heavy rain in the Portage area. Overnight, this first wave of the storm has added 5-12″ of moist snow above ~1,500′ and .5-1″ of rain below with Portage Valley seeing up to 2″ of rain at sea level. Ridgetop winds have been Easterly in the 20-30mph range. Temperatures along ridgelines have stayed in the 20’sF, while at 1,000′ sit in the mid 30’sF after warming to near 40F yesterday.
Today, Sunday, rain and snow will continue as this system looks to peak today. Another .5-1″ of rain is expected to fall below 2,500′ with 5-12″ of snow above this. Portage, and coastal zones, should continue to see twice as much precipitation as the Turnagain/Girdwood areas. Ridgetop winds will stay strong, in the 20-35mph range from the East. Temperatures also will remain in the 20’sF along ridgelines and in the mid 30’s at 1,000′.
For Monday, a break in the storm is expected before another round moves in Tuesday. Cloudy skies, light precipitation with a rain/snow line around 2,000-2,500′ and moderate Easterly winds should be seen Monday.
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
Center Ridge (1880′) | 35 | 6 | 0.5 | 69 |
Summit Lake (1400′) | 35 | trace rain | trace | 20 |
Alyeska Mid (1700′) | 34 | ~4 | 0.5 | 61 |
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
Sunburst (3812′) | 24 | NE | 20 | 50 |
Seattle Ridge (2400′) | 29 | ESE | 18 | 46 |
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.