Winds over the last day have blown enough to transport snow and create new slabs 2-3’ in depth in the higher elevations. Winds today out of the East will continue to build slab depths on leeward slopes. We currently have very limited information from the upper elevations. If venturing into the higher elevations today, treat wind loaded areas with a healthy dose of suspicion. Wind slabs that have formed over the past day and continue to build today have the potential to slide easily. This problem on its own is enough to bury a person. Add into the mix the chance of triggering a deep slab and the end result could be grim.
It is important to know how to recognize snow that has been wind loaded. Smooth, rounded and pillowy are a few ways to describe the look of wind slabs. Snow will feel more stiff in wind loaded areas. Shooting cracks are an obvious sign of a wind slab that is unstable.
This past weekend brought much needed precipitation to the area. Rain fell up to 2,500’ but changed over to snow by Friday afternoon. The upper elevation starting zones have received well over 2’ of snow in the past 3 days. At the bottom of the snowpack, up to 5’ down in some locations, is weak snow. In many places it will be difficult to impact that weak snow that is far below you. However, snow does not sit uniformly across the mountains. Snow depths will vary from 1-5 feet in the upper elevations. It is in these spots with thin snow coverage that need to be avoided. The likelihood of triggering a deep, unsurvivable slab will go up if people hit thin spots. The obvious signs of unstable snow will not necessarily be present. Snowpit tests may or may not always point to this problem. In order to understand this problem it is crucial to know the history of the season up to this point. History tells us that the foundation is weak and not trustworthy.
This video shows the problem. It takes a lot of force to trigger a slab in this test. Once it does fail the entire snowpack (column in this case) slides.
Warm temperatures and rain have done a number on the snowpack at the lower elevations. Warm temperatures in the lower elevations will persist throughout the day. While the chances of wet slabs releasing have gone down over time, the threat of dangerous wet loose avalanches is something to be aware of. Avoid steep terrain in the lower elevations today. If your snowmachine, skis or board is punching through the entire snowpack, it is definitely time to back off of steep terrain. Pay attention to what is below as well. Terrain traps such as trees, cliffbands and gullies will amplify the consequences of being caught in a wet loose avalanche today.
In the past 24 hrs the mountains around Eastern Turnagain Arm have received 6 € of new snow with .6 € of water equivalent. Ridge top winds have been out of the East averaging 36 mph with gust to 86 mph. Temperatures have continued to remain mild, with freezing level up to 2,000′ overnight. The Sunburst station at 3,812′ has averaged 22 deg F.
Today expect light snow/rain and mild temperatures. Winds will be out of the East at 40 to 50 mph. Snowfall in the upper elevations will accumulate up to 3 € with rain/snow line around 1,300 feet above sea level. Temperatures at 1,000′ will be in the high 30s F.
We will remain under the influence of an active weather pattern and a general Southerly flow over the next several days. Expect temperatures to remain mild and precipitation to be on and off through the week.
|05/06/20||Turnagain||Avalanche: Pastoral Peak, north face||Andy Duenow|
|04/10/20||Turnagain||Avalanche: Wolverine||Mike Records|
|04/10/20||Turnagain||Observation: Eddies lookers right shoulder||Matt Yoder|
|04/09/20||Turnagain||Observation: Bench Peak||Mike Records|
|04/04/20||Turnagain||Observation: Pete’s North||Anonymous|
|03/26/20||Turnagain||Avalanche: Tincan – Proper (SW facing)||CNFAIC Staff|
|03/26/20||Turnagain||Avalanche: Seattle Ridge||W Wagner Forecaster|
|03/25/20||Turnagain||Avalanche: Sunburst Uptrack @ 2000′||J. Boisvert|
|03/24/20||Turnagain||Observation: Turnagain – Road Observations||W Wagner Forecaster|
|Area||Status||Weather & Riding Conditions|