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

Mar 30th, 2014–Mar 31st, 2014

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

Regions

Olympics.

Sunday may continue to be a tricky day to manage avalanche concerns. Winter like wind and storm slab should prevail at higher elevations with wet loose concerns at lower elevations. Heavier showers and strong spring solar effects can quickly change the snow conditions so pay close attention to weather through the day.   

Detailed Forecast

Light occasional moderate showers should be seen on Sunday in the Olympics with fairly cool temperatures.

Watch for areas of wind slab from the previous couple days lingering on lee slopes. This is most likely on north to east slopes near and above treeline. Watch for signs of cracking or firmer wind transported snow and approach open lee slopes with caution.

New or new storm slab may not have stabilized yet on Sunday. This will also be likely on sheltered slopes where there was heavy snowfall or graupel which may have formed temporary weaker storm layers also near and above treeline.

Despite the mostly cloudy weather and cool temperatures on Sunday wet loose avalanche conditions are likely mainly on solar slopes near and below treeline. Watch for wet surface snow deeper than a few inches, roller balls in surface snow and small natural wet loose releases that usually precede more major wet loose snow avalanches. And remember brief sun breaks can quickly extend the wet loose concern to above treeline or to other aspects.  Avoid terrain traps where a small but powerful wet loose avalanche could have unintended consequences.

Snowpack Discussion

Fair weather was seen last weekend through Monday with Monday the warmest day. Reports from the Cascades during this period indicated some powder surviving on north slopes and wet loose avalanches on solar slopes. A crust should have formed on most solar slopes.

The weather pattern got activated again over the Northwest starting Tuesday. There has been about 1.5 feet of snowfall in the 4 days ending today at the NWAC station at Hurricane Ridge. There will have been less snowfall and rain at lower elevations. So it is getting to be a mix of winter like conditions at higher elevations and spring like conditions on solar slopes and at lower elevations.

A frontal system passing through on Friday brought moderate south winds and wet snowfall at Hurricane Ridge, with rain likely not far below in elevation. NWAC observer Katy Reid at Hurricane on Friday reported local wind slab along along lee ridges with pit tests giving stubborn but clean shears. She also found some storm snow instabilities giving clean results in hand tests at about 15 cm or 6" below the surface.

Hand pit results at Hurricane Ridge on Friday by NWAC observer Katy Reid.

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.

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.