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

Apr 7th, 2017–Apr 8th, 2017

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

Regions

.

The avalanche danger will increase with elevation on Saturday creating dangerous avalanche conditions above treeline. Careful snowpack evaluation and cautious routefinding will be essential.

Detailed Forecast

Greatly decreasing winds, showers at higher elevations and cooler temperatures should be seen on Saturday. But the avalanche danger will still increase with elevation on creating dangerous avalanche conditions above treeline.

New wind slab may be found on various aspects above treeline due to the recent and latest strong and shifting winds. This avalanche problem may also creep down into the near treeline.

Loose wet avalanches at lower elevations may remain active on Saturday. Watch for wet surface snow deeper than a few inches, pinwheels and initial natural releases that indicate an increasing loose wet avalanche danger. Be wary of steep slopes with terrain traps such as cliffs or if heavily treed, where even a small loose wet avalanche could have big consequences.

Recent cornices are very large and have likely been weakened during this most recent storm cycle. Natural cornice releases and resulting slab avalanches are dangerous and unpredictable. Give cornices a wide berth if traveling along ridge-lines and avoid slopes below large cornices. See a blog post regarding cornices here.

Other avalanche problems not listed that may be encountered on Saturday include storm slab in more sheltered areas above treeline that experienced rapidly accumulating snowfall for more than a few hours.

Remember that solar effects can rapidly increase the touchiness of various type of avalanches at this time of year.

Snowpack Discussion

Weather and Snowpack

March was a wet and wild month for weather and avalanches in the Cascades. The last widespread avalanche cycle during this stretch occurred March 28th-29th.

Fair but cool weather has been seen in the Cascades Monday and Tuesday. Reports generally indicate strong surface or near surface crust layers and shallow recent snow. 

A stalled frontal boundary on Wednesday to Thursday morning brought heavy rain and snow to Mt Baker with light rain or snow for the rest of the Cascades. Snow levels were generally between 4500-6000 feet. For the 3 days ending Friday morning NWAC stations along the Cascade east slopes had about an inch of WE which will have fallen as snow above the snow levels.

A deep low pressure system moved north just off the Washington coast on Friday. SSE flow aloft Friday morning will shift to the SW by Friday night. Snow levels are running in the 4-5000 foot range on Friday. By Saturday morning 24 hour WE at NWAC stations along the Cascade east slopes should get another .25-.75 inches of WE which will fall as snow above the rather low snow levels.

Recent Observations

North

No recent observations.

Central

NWAC pro-observer Tom Curtis was at Blewett Pass on Friday and above about 5000 feet reported a thin crust over moist to wet rounded poly crystals with increasing density with depth and no current avalanche problems. Most SW-W slopes had little snow.

South

No recent observations.

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.

Loose Wet

Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.