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

Dec 15th, 2015–Dec 16th, 2015

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

Regions

Olympics.

Previous wind and storm slab layers from the weekend should be the main concerns on Wednesday. Greater caution would be necessary if the weak front Tuesday night and Wednesday morning brings more snow than expected.

Detailed Forecast

A weak cold front will cross the Northwest Tuesday night and Wednesday morning. This may bring some very light amounts of new snow but should not greatly change conditions. Some fair weather should be seen by Wednesday afternoon. Light or moderate northwest winds and cool temperatures should also continue on Wednesday.

Previous wind slab layers from the weekend will possibly linger on previous lee mainly north to east slopes near ridges and summits on Wednesday. Storm slab from the weekend should become unlikely by Wednesday but would be found in what were calmer areas if it still exists.

Use more caution and watch for new small wind slab or small storm slab if the weak front Tuesday night and Wednesday morning brings more snow than expected.

Terrain anchors are still causing significant anchoring at the lowest elevations. Use caution near creeks which are still open in some areas.

Snowpack Discussion

An atmospheric river caused warm very wet weather last week. This caused consolidation and stabilizing of the older part of the Olympics snowpack with the Waterhole snowdepth dropping to around 18 inches.

A stormy pattern with cooling was seen late last week and over the weekend with about 2.5 feet of snowfall at Hurricane.

A Park Ranger at Hurricane Ridge Sunday midday reported a storm slab release below the Sunrise Ridge likely on an east facing slope near Hurricane. The slide was likely triggered but this was not confirmed.  The avalanche crown was estimated at 2-3 feet and released about 150 wide and ran about 100 feet vertical - big enough to get into serious trouble.

Cool weather with little new snow has been seen Monday and Tuesday. This will have mostly caused some consolidation and further stabilizing.

 

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.

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.