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Archived

Avalanche Forecast

Jan 31st, 2015–Feb 1st, 2015
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Olympics.

Shallow storm slabs are possible on lee northerly terrain near and above treeline Sunday. 

Detailed Forecast

An incoming frontal system will bring light rain and snow to the Olympics on Sunday. Snow levels should fluctuate around 5000 feet. New snow may bond poorly to surface crusts on northerly aspects near and above treeline, allowing shallow storm slabs to develop. 

The increasing avalanche danger Sunday will be relegated to aspects and elevations with existing snow cover. 

Snowpack Discussion

Mainly mild and sunny weather over the past week has further melted away most of the remaining snow at Hurricane.

NWAC pro-observer Katy Reid visited Hurricane last Sunday, Jan 24th and reported very low snow cover with snow-free areas on solar slopes. There were no avalanche problems near and below treeline due to lack of snow. 

On Jan 25th Katy ventured toward Mt. Angeles. She found snowdepths averaging 40-80 cm on N aspects with a few drifts above 1 meter. Snow cover was patchy only a few hundred feet below the ridge even on N slopes. This snow was well bonded consisting of melt forms and crusts and did not pose an avalanche problem.

Video cam images via the Park Service web page look more like June than January at Hurricane Ridge!

Avalanche Problems

Storm Slabs

Release of a soft cohesive layer (a slab) of new snow that breaks within the storm snow or on the old snow surface. Storm-slab problems typically last between a few hours and few days. 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.

 

You can reduce your risk from Storm Slabs by waiting a day or two after a storm before venturing into steep terrain. Storm slabs are most dangerous on slopes with terrain traps, such as timber, gullies, over cliffs, or terrain features that make it difficult for a rider to escape off the side.

 

Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 1