Mt Hood

Issued: 7:48 PM PST Thursday, March 8, 2018
by Josh Hirshberg

NWAC avalanche forecasts apply to backcountry avalanche terrain in the Olympics, Washington Cascades and Mt Hood area. These forecasts do not apply to developed ski areas, avalanche terrain affecting highways and higher terrain on the volcanic peaks above the Cascade crest level.

You can trigger wind slab or storm slab avalanches and the possibility of natural avalanches will remain into the day. Steer around wind drifts on lee slopes near and above treeline and avoid wind-stiffened snow, fresh cornices, or snow pillows. Storm slab will be reactive in wind-sheltered locations. Avoid open slopes steeper than 35 degrees. Large wind slabs may release from high on Mt. Hood, so stay out from under large avalanche paths.

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Avalanche Problems for Friday

Wind Slabi

Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.

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Storm Slabsi

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.

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Forecast for Friday:

Large wind slabs may release from high on Mt. Hood, so stay out from under large avalanche paths.

Natural avalanches are possible on Thursday and human triggered avalanches are likely Thursday morning, particularly, as moderate precipitation through Thursday night combines with strong winds creating significant unstable wind slab which may still be quite reactive. Avalanche danger will decrease as temperatures gradually rebound and mostly cloudy skies prevail on Friday. In the NWAC rated near and above treeline terrain, watch for cracking, wind stiffened snow, and freshly formed drifts. Steer around fresh wind features, convex rolls, and slopes holding a foot or more of new, cohesive snow that are 35 degrees and steeper. Shallow Storm Slabs may develop by the afternoon in wind sheltered terrain. The avalanche danger will continue to increase Thursday night. 

Heavy, dense snow from Thursday afternoon through Thursday night is creating storm slabs near and below treeline. These slabs are likely to be reactive, particularly in the morning hours. The snow will be wet and heavy, particularly down low, so expect these slabs to glide slightly slower than normal, but have a lot of power.


Avalanche Summary:

Snow levels dropped on Thursday, averaging about 4500-5000 feet and a storm brought .5" of snow water equivalent. Winds increased into the moderate to strong range and visibility was reported by Hood Meadows patrol as a whiteout during the afternoon, limiting snowpack observations. However, it can be assumed that large wind slabs were forming near and above treeline and storm slabs may have been beginning to develop in wind-sheltered locations given high precipitation rates Thursday afternoon. The cooler temperatures on Thursday likely created a crust near and below treeline from the moistened snow surfaces created by above-freezing temperatures and overcast skies on Wednesday. 

Loose wet avalanches were reported Tuesday on sunny aspects.

The recent warm weather should have reduced the reactivity of the prior 8" shallow wind slab that formed on lee (easterly) slopes Sunday night and Monday morning. 

In many locations more than 3’ of snow now sits on a firm buried crust layer (2/17). This crust has been reported up to 6600’ by professionals in the region. There are currently no significant layers of concern below the 2/17 crust.


NWAC pro-observer Laura Green was in Mitchell Creek Monday and observed active wind loading occurring near and above treeline. No new or recent avalanches were observed.

On Monday, Mt. Hood Meadows Pro Patrol reported west winds transporting snow, 8" of new and generally non-reactive wind slab on lee aspects limited to E facing slopes. Winds eased mid-day. Small loose wet avalanches occurred on solar, especially below treeline.

No Corresponding Mountain Weather Forecast Available


This Backcountry Avalanche Forecast is provided in conjunction with the US Forest Service, and is intended for personal and recreational purposes only. Safe backcountry travel requires preparation and planning, and this information may be used for planning purposes but does not provide all the information necessary for backcountry travel. Advanced avalanche education is strongly encouraged.

The user acknowledges that it is impossible to accurately predict natural events such as avalanches in every instance, and the accuracy or reliability of the data provided here is not guaranteed in any way. This forecast describes general avalanche conditions and local variations will always occur. This forecast expires 24 hours after the posted time unless noted otherwise.