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The avalanche danger is CONSIDERABLE as a warm storm has brought over 2′ of snow to upper elevations and rain on snow to lower elevations, making large human triggered avalanches likely and natural avalanches possible. Two days of above-freezing temperatures will make it likely we could see very large wet slab avalanches failing deeper in the snowpack. Dangerous avalanche conditions will require cautious terrain use today, which means avoiding steep terrain and limiting time spent in runout zones below steeper avalanche paths.
PORTAGE/PLACER VALLEYS: These areas have gotten 2-3′ snow at upper elevations, with 2-3″ rain on snow at lower elevations. This will make it likely to see natural avalanches running long distances into valley bottoms. Very dangerous avalanche conditions exist, and travel in or below avalanche terrain is not recommended.
End of Season Operations: Forecasts will be issued on Tuesday, Thursday, Saturday and Sunday through the end of April. If a dramatic change in avalanche conditions occurs on an off day, we will provide a forecast. The final forecast will be on Saturday, April 30th.
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 |
Since the snow (and rain) started falling Thursday night, we have received 2-3″ water, which has amounted to 2 feet or more snow in the alpine, and has fallen as almost all rain below 1000′. This includes 1-1.5″ water in the past 24 hours for Turnagain Pass and Girdwood, and 2.8″ water in Portage. We have seen rain on snow at elevations as high as 1900′, and the old snow did not get a chance to re-freeze ahead of the storm at elevations below around 1800′. With over 48 hours of above freezing temperatures, conditions are primed to see continued very large wet slab avalanche activity similar to the one on Raggedtop Thursday evening.
These large avalanches have the potential to run long distances into valley bottoms, and are nothing to mess with. This means we will need to avoid spending time in avalanche runout zones, as well as on steep avalanche-prone terrain. As Wendy mentioned in yesterday’s advisory, these next few days will most likely mark the start of our springtime shed cycle. We need to navigate the backcountry carefully as things start to fall apart.
Wet Loose Avalanches will be likely at elevations below 1900′, where the storm is finishing as rain on snow. These can be big enough to be dangerous on their own, and they also have the potential to pull out larger wet slabs. Just one more reason to avoid steep slopes today.
Cornices were already massive ahead of this round of stormy weather, and they are being pushed towards their breaking point. As always, be sure to limit time spent traveling under them, and keep plenty of space from the edge if you are traveling along ridgelines.
Glide Avalanches have been releasing across the area, and are expected to continue to release with above-freezing weather. They are large and unpredictable, so be sure to avoid lingering below glide cracks.
The storm from the past two days has put a heavy load on a wet snowpack, with rain on snow up to around 1900′. This will make for dangerous avalanche conditions today. 04.22.2022
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 |
This storm has brought over 2′ of snow in the upper elevations. Winds have been blowing 20-40 mph out of the east with gusts of 55-65 mph, and are expected to stay strong this morning before slowly calming down later in the day. This is a significant loading event, and will make for continued dangerous avalanche conditions today even as the storm subsides. Human-triggered storm slab avalanches up to 2′ deep or deeper will be likely, with even bigger wind slab avalanches on upper elevation slopes that have been getting loaded by the strong winds since the storm began.
This storm snow is falling on a mix of weak surfaces. On upper elevation northerly aspects, fresh storm slabs are sitting on dry, faceted snow. The storm buried a crust on all other aspects at elevations above 2000′. On lower elevations, the old snow did not have a chance to refreeze before the storm picked up, which will make for a whole other set of wet avalanche problems (mentioned in problem 1 above).
The avalanche conditions today are very different from what we have been enjoying over the past two weeks. Dangerous conditions will require cautious terrain use. We will need to take a step back and avoid traveling on steep terrain, and limit time spent in avalanche runout zones. If the sun is able to come out for any amount of time this afternoon, be on the lookout for increasing avalanche danger as the new snow heats up.
Yesterday at Tincan was a stark contrast to the conditions we have been enjoying for the past two weeks. 04.22.2022
Click here to view the video from the field yesterday if it doesn’t load in your browser.
Yesterday: Heavy snowfall brought 1-1.5″ water, with rain as high as 1900′. Upper elevations received 1-1.5′ snow since yesterday morning, with over 2′ snow since the storm started Thursday afternoon. High temperatures were in the upper 20’s to upper 30’s F, with overnight lows in the mid 20’s to mid 30’s F. Skies were obscured, with easterly winds of 20-40 mph and gusts of 55-65 mph.
Today: The storm is slowly tapering off, and is expected to bring a trace to 2″ new snow above 1900′. Winds are looking to calm down during the day today, with continued strong easterly winds this morning at 25-30 mph, dropping to around 10 mph this afternoon. Skies will be mostly cloudy, with some brief periods of sun possible in the afternoon. High temperatures will be in the low 30’s to low 40’s F, with lows in the upper 20’s to low 30’s F.
Tomorrow: The weather is looking to quiet down tomorrow, with mostly cloudy skies and high temperatures in the mid to upper 30’s F. Winds will be light and variable, and no precipitation is expected. With continued warm temperatures, we are anticipating very dangerous avalanche conditions next time the sun makes an appearance. Be sure to stay tuned for more.
PRECIPITATION 24-hour data (6am – 6am)
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
---|---|---|---|---|
Center Ridge (1880′) | 34 | 9 | 1.5 | 115 |
Summit Lake (1400′) | 35 | 0 | 0.1 | 34 |
Alyeska Mid (1700′) | 33 | 2 | 0.65 | N/A |
RIDGETOP 24-hour data (6am – 6am)
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
---|---|---|---|---|
Sunburst (3812′) | 24 | ENE | 31 | 65 |
Seattle Ridge (2400′) | 28 | SE* | 16* | 35* |
*Seattle Ridge anemometer has been rimed up and not reporting since 4:00 p.m. yesterday.
Date | Region | Location | Observer |
---|---|---|---|
10/27/24 | Turnagain | Observation: Tincan | Michael Kerst |
10/21/24 | Turnagain | Observation: Turnagain Pass Road Observation | Trevor Clayton |
10/19/24 | Turnagain | Observation: Tincan – Below Todds Run | Andy Moderow |
10/18/24 | Turnagain | Observation: Taylor Pass | Eli Neuffer |
10/15/24 | Turnagain | Observation: Tincan Common | John Sykes Forecaster |
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 |
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