Small wet loose avalanches were observed yesterday and remain a concern today as temperatures remain unseasonably warm and the sun shines on the snow. It will be crucial today to pay attention to changing conditions and adjust travel to avoid hazard. Springtime travel in avalanche terrain is generally safer in the morning when the slopes are more frozen. If heading out note that the temperatures overnight were higher than the past two nights especially in the mid-elevation band and there may be a longer stretch of above freezing temperatures today. The Alpine may see some of the highest temperatures yet. Increasing cloud cover is in the forecast for the day and has the potential to trap more heat and “greenhouse” the snow. Pay attention to crust supportability, if you are sinking in on your skis or trenching on your machine or dropping in with your boots it’s a good idea to get off the slope. In the Alpine drier snow may feel like mashed potatoes as it heats up. Look for roller balls and push-a-lanche conditions i.e. small avalanches initiating from skis or machine starting to entrain snow. Plan your route to avoid travel on or under steep, solar slopes later in the day and recognize that the greenhouse effect could warm shaded aspects in the Alpine as well. Choose terrain carefully!
Do you know what aspect you are on? What elevation are you traveling at? Do you need to travel on or under snow that is heating up? Looking towards Taylor Pass, 3-25-19
Yesterday we received a report of a large natural slab avalanche that was observed running later in the day in terrain north of Girdwood. The details are limited but this was on a southeast aspect around 4500′ and was classified as a D3, which is quite large and destructive. It was wide and the crown was deep. Although this is out of the Advisory Area, and may be somewhat of an outlier type of avalanche, it is important to remember that the colder snow in the Alpine is now getting warmed by direct sunshine and rising temperatures. Again, avoiding travel on or under steep, solar aspects later in the day is prudent at this time of year. The warming of the potential slab also adds to the lingering concern of triggering an avalanche that fails on an old persistent weak layer. Finding the trigger spot in a thin area of the snowpack could produce a very large avalanche. Signs of instability won’t necessarily be present with this type of avalanche problem. Use good travel protocol and think about consequences if a slope does slide. It could be the 1st or 10th skier or machine on the slope that triggers the avalanche. In addition, if traveling in the Alpine look for areas that are more wind-loaded, watch for cracking and listen/feel for hollow snow indicating wind slabs in upper elevation terrain.
CORNICES: Cornices are very large and warm air temperatures and direct sunshine could destabilize them today. They have the potential to trigger very large avalanche on the slopes below and break way farther back than expected. Give them a wide berth.
Deep avalanche in 20-Mile that ran during the last storm, photo: 3-25-19. Deep persistent slab avalanches continue to be a concern.
There were a few new glide avalanches observed in the Girdwood Valley yesterday and many glide cracks are opening around the advisory area. These are very unpredictable and not triggered by humans. Glide avalanches fail at the ground pulling out the entire season’s snowpack and could be very dangerous. The only way to avoid this hazard is by not spending time under terrain with glide cracks.
Glide cracks on Seattle Ridge that could run into traveled terrain. 3-25-19. Avoid spending time underneath glide cracks!
Yesterday: Mostly sunny skies with highs in the 40Fs at lower elevations and highs in the 30Fs at upper elevations. Overnight temperatures barely dipped below freezing on a few weather stations but generally temperatures were in the mid to high 30Fs. Skies were mostly clear initially but became partly cloudy and winds were easterly 5-10 mph with gusts into the teens.
Today: Skies are forecast to be partly sunny with temperatures in the Alpine in the mid to high 30Fs and temperatures in the 40Fs at lower elevations. Winds will remain easterly 5-15 mph with gusts into the teens. Overnight will be partly cloudy becoming mostly clear. Temperatures will be in the high 20Fs to mid 30Fs.
Tomorrow: More sunshine and warm temperatures with clouds building overnight. Cloudy skies will continue Friday but will clear for the weekend as the next ridge of high pressure sets up and dictates the weather into next week.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||36||0||0||70|
|Summit Lake (1400′)||34||0||0||23|
|Alyeska Mid (1700′)||36||0||0||65|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||34||variable||2||20|