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 5th, 2016–Feb 6th, 2016

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

Regions

Olympics.

New wind and storm slab layers should be seen on Saturday. The skiing should be improved but don't forget to make careful snowpack evaluations.

Detailed Forecast

Strong southwest winds aloft will accompany a cold front will cross the Northwest on Friday evening. West winds will follow with orographic snow showers and a good cooling trend on Saturday morning.

The cooling trend may help bond new snow to old snow surfaces where the snow starts at above freezing temperatures. With a little luck Hurricane will have several inches or better of new snow by the time snow showers taper off on Saturday.

The main avalanche problem should be new wind slab on lee slopes in the near and above treeline. Watch for signs of snowpack cracking and firmer wind transported snow on lee slopes.

A secondary avalanche problem should be new storm slab in areas with less wind if there is rapid loading. The cooling trend may help limit this avalanche problem.

 

 

Snowpack Discussion

The last heavy rain fell in the Olympics January 27th-28th with over 2 inches of rain recorded at the NWAC station at Hurricane Ridge.

The "20th of June" path released as a wet slab during the rain and warmth January 27th. Photo: January 29th by Matt Schonwald.

A strong occluded front with strong winds crossed the Northwest January 29-30th. Hurricane Ridge had about 14 inches snowfall.

NWAC pro-observer, Matt Schonwald visited Hurricane January 29th and found rapidly building wind slab and extensive loading on lee slopes in all 3 elevation bands. New cornices were sensitive to triggering but still relatively small. 

Cool, benign weather followed Sunday through Tuesday. A sun crust formed on many solar slopes and surface hoar was seen on many non-solar slopes in the Cascades so this is possible in the Olympics as well.

A cold front and then a warm front crossed the Northwest on Wednesday and Thursday. The Hurricane ranger reported about 8 inches of snowfall for the 2 days ending Friday morning.

Hurricane Ridge was living up to it's name today and unfortunately the road was closed due to storm conditions and NWAC pro-observer Matt Schonwald could not make it up to the Ridge.

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.