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 12th, 2016–Jan 13th, 2016

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

Regions

Mt Hood.

Shallow storm and wind slab avalanches are possible by Tuesday afternoon as snowfall rates and transport winds increase later in the day. If storm conditions develop faster than expected, change your travel plans accordingly for the increased hazard. Look for a rapidly increasing avalanche hazard Tuesday night! 

Detailed Forecast

An incoming frontal system on Tuesday should largely stall along the coast during the day with periods of rain and snow for Mt. Hood. More moderate precipitation and stronger transport winds and a warming trend should hold off until Tuesday evening. 

Shallow storm and wind slab avalanches are possible by Tuesday afternoon as snowfall rates and transport winds increase later in the day. North through Southeast aspects should continue to see additional light loading near and especially above treeline Tuesday. Watch for signs of firmer wind transported snow that can indicate wind slab layers near and below ridges. If storm conditions develop faster than expected, change your travel plans accordingly for the increased hazard. 

Shallow loose wet avalanches are possible Tuesday mainly below treeline on steeper slopes for areas away from the Passes that see warming or light rainfall and have received new snowfall.

Look for a rapidly increasing avalanche hazard Tuesday night! 

 

Snowpack Discussion

About a week of fair weather was centered around the New Year. This allowed the heavy snow that fell during the strong storm cycle that ended about Christmas to settle and stabilize. By New Years Eve through last weekend moderate to strong east-northeast winds had significantly scoured most of the available surface snow, mainly in the near and above treeline elevation bands.

No avalanches have been reported over the past several days on Mt Hood. Light precipitation with a steady and mild snow levels have accumulated a few inches of snow by Tuesday afternoon near and above treeline, with stronger SW winds above treeline likely forming new wind slab on lee easterly slopes. 

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.