Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Feb 13th, 2019–Feb 14th, 2019

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.

Regions

.

Dangerous and complex avalanche conditions exist throughout the North Cascades. You can trigger an avalanche within new snow, or on an unpredictable persistent weak layer. Carefully evaluate the snowpack and use extra caution near steep unsupported slopes.

Discussion

Snow and Avalanche Discussion

The Mt. Baker area received just over 30in of low-density of snow (2.18in SWE) since Monday. The new snow fell on layers of unconsolidated snow making for bottomless travel conditions. Cold temperatures and light to moderate winds accompanied the storms. Plenty of snow is available for transport. On Thursday, expect increasing easterly winds, light snowfall, and warming temperatures in the afternoon.  

On Wednesday, the storm snow settled, skies cleared, and the sun came out. In some areas, the storm snow became more cohesive, formed slab properties, and was more reactive by mid-day. Natural and triggered avalanches were reported throughout the Hwy 542 corridor: Shuksan Arm, Bagley Lakes, Glacier Creek, and Canyon Creek. Most notable was a remotely triggered avalanche on a north aspect at 5200ft in the Excelsior Ridge area that broke 3ft deep and 100ft wide. Numerous natural and triggered storm slab avalanches failed within new snow breaking 1-2ft deep and 50-75ft wide. Small to large storm slab avalanches occurred in all elevation bands and on all aspects. A few natural avalanches failed near and above treeline on solar aspects on an older layer of weak snow buried on February 8th -  the same layer that was the culprit in a remotely triggered avalanche on Ptarmagin Ridge over the weekend. Observers noticed plenty of unconsolidated surface snow and significant sloughing on slopes steeper than 35 degrees. When the skies cleared, steep sun-exposed slopes produced small wet loose avalanches.

We have received a lot of snow over the past few days. These are the conditions when tree well and snow immersion suffocation accidents occur. Don't travel alone, and keep eyes on your partners. Check out https://www.deepsnowsafety.org/ for more information. 

Snowpack Discussion

Regional Synopsis coming soon.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.