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

Jan 22nd, 2015–Jan 23rd, 2015

Alpine
Natural avalanches unlikely, human triggered possible.
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

Mt Hood.

The avalanche danger should increase less at Mt Hood on Friday than in the Washington Cascades. But be sure to watch for loose wet or wet slab conditions.

Detailed Forecast

West flow and an atmospheric river (aka the Pineapple Express) of warm front moisture will begin moving over the upper ridge and to the Northwest on Friday. Rain or snow should become moderate to heavy mainly in the Olympics and north to central Cascades by Friday afternoon and continue Friday night with rising snow levels.

In all areas west of the crest loose wet and and wet slab avalanches will be listed at the avalanche problems on Friday. These problems are more likely in areas of the Washington Cascades with the most recent snowfall and expected greater rainfall on Friday.

Often loose wet avalanches occur just prior to wet slab avalanches. Avoid steep slopes if you are in increasing heavy rain and start to see wet snow deeper than a few inches or increasing natural pinwheels or rollerballs.

 

Snowpack Discussion

Snow on the back end of the last storm Sunday and Monday was only in the 5-6 inch range at Mt Hood.

NWAC pro-observer CJ Svela was at Timberline on Sunday and reported new snow over a breakable crust. Rounded grain and melt form layers in the mid pack seemed to lack consistent shears and tests did not indicate propagation.

The Meadows patrol reported crusts and melt forms in the upper pack on Wednesday with good stability. Some cool snow from the last storm was seen on N-NE slopes.

The mid and lower snowpack at Mt Hood should also mainly consist of crusts and stabilized rounded grain or melt form layers from warm  periods so far this winter.

A weak dissipating front is moving across the Olympics and Cascades on Thursday. Snow and rain amounts are expected to be light and not have a great effect on snow conditions.

Problems

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.

Wet Slabs

Wet Slab avalanches are the release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slabs can be very unpredictable and destructive.