Turnagain Pass
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The Bottom Line
The avalanche danger above 2500′ is CONSIDERABLE. Human triggered avalanches are likely and naturals are still possible. The Alpine received heavy snow with strong winds yesterday and the snowpack needs time to adjust. Below 2500′ where most of the precipitation fell as rain the danger is MODERATE. There is no snow below 1000′ and NO RATING.
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| 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. |
| 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 |
Yesterday was an impressive weather event with 2.5-3.5 inches of water falling within 24 hours and sustained easterly winds 30-40 mph gusting into the 80s. With unseasonably warm temperatures the rain/snow line was somewhere above 2500′. This means upper elevation terrain saw 2-3′ of snow. Being well within the 24-48 hours after the storm, human triggered avalanches are likely today in the Alpine. Warm snow fell over colder snow potentially forming storm slabs. Expect cornices to have grown and wind slabs to still be touchy in leeward terrain. Look for signs of instability and pay attention to surface conditions. Where did the strong winds deposit all the snow?
Below 2500′ it may be possible to trigger some type of wet avalanche in the saturated snowpack. There were a couple of different crust layers in this elevation band prior to the storm, these may act as a sliding surface if they did not deteriorate in the rain. Watch for push-a-lanche conditions (snow easily moving from your skis and entraining snow below) in steep terrain. If skies clear at all and/or temperatures cool a crust will form and any remaining hazard will decrease.
One hour precipitation graph from the base of Alyeska. Courtesy of Mesowest/MADIS.
Rain runnels on Tincan prior to the storm starting on Sunday. What will it look like today???
| 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 facet/crust combination near the base of the snowpack in the Alpine may have been overloaded by yesterday’s storm or teetering on the brink. We will be looking for evidence of natural avalanches failing close to the ground in the upper elevation terrain and investigating whether or not this layer remains reactive or goes dormant after the additional snow load. Keep this in mind if traveling above 2500′.
Yesterday: Obscured skies and heavy precipitation through most of the day. Easterly winds 20-40 mph gusting into the 80s. Temperatures ranged from the high 20Fs/low 30Fs at ridgetops to the high 40Fs at sea level. Precipitation eased off around 8pm and winds speeds decreased to teens and 20s. Temperatures remained steady overnight.
Today: Mostly to partly cloudy skies with a chance of rain/snow showers. Temperatures will be in the high 30Fs to low 40Fs at sea level and in the high 20Fs to low 30Fs at upper elevations. Winds will be easterly 10-20 mph with gusts into the 30s. Overnight temperatures will cool slightly and there is a chance of rain/snow showers.
Tomorrow: Mostly cloudy with rain and snow showers. Temperatures will be in the mid to high 20Fs at ridgetops and in the mid 30Fs to low 40Fs at sea level. Winds will be easterly 15-25 gusting in 30Fs. The overall pattern for the week looks to be cloudy with rain/snow showers and mild temperatures.
PRECIPITATION 24-hour data (6am – 6am)
| Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
|---|---|---|---|---|
| Center Ridge (1880′) | 36 | 1 | 2.9 | 19 |
| Summit Lake (1400′) | 36 | 0 | 2.3 | 7 |
| Alyeska Mid (1700′) | 36 | 0 | 3.24 | 17 |
RIDGETOP 24-hour data (6am – 6am)
| Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
|---|---|---|---|---|
| Sunburst (3812′) | 27 | NE | 38 | 107 |
| Seattle Ridge (2400′) | NA* | SE | 24 | 53 |
*Seattle Ridge temperature sensor is not functioning.
| Date | Region | Location | Observer |
|---|---|---|---|
| 10/14/24 | Turnagain | Avalanche: Tincan | CNFAC Staff |
| 05/13/24 | Turnagain | Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South | H Thamm |
| 05/13/24 | Turnagain | Observation: Turnagain Pass non-motorized side | Amy Holman |
| 05/12/24 | Turnagain | Observation: Warm up Bowl | Tony Naciuk |
| 05/07/24 | Turnagain | Observation: Turnagain Pass Wet Slabs | A S |
| 04/29/24 | Turnagain | Avalanche: Turnagain aerial obs | Tully Hamer |
| 04/27/24 | Turnagain | Observation: Johnson Pass | Noah Mery |
| 04/23/24 | Turnagain | Observation: Turnagain Sunny Side | Travis SMITH |
| 04/21/24 | Turnagain | Observation: Bertha Creek | Anonymous |
| 04/20/24 | Turnagain | Avalanche: Spokane Creek | Schauer/ Mailly Forecaster |
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