Avalanche Forecast

Southwest flow should carry an energetic front and shortwave to the Northwest Saturday evening and night. Moderate west flow should carry a 2nd short wave, an upper low and a cool unstable air mass to the Northwest Sunday. This should cause southwest to west winds, rain or snow changing to snow showers and lowering snow levels on Sunday. Snow and snow showers should cause ball park about 12 inches of snow at Mt Hood by the end of the daylight hours on Sunday. There is a chance of thunderstorms in the forecast along the west slopes Sunday afternoon and evening.

A mix of likely dangerous winter and spring avalanche conditions is likely at Mt Hood on Sunday. The sun is getting much stronger and new snow may be very reactive to solar effects. The greatest danger should be in the afternoon to the end of the daylight hours.

New wind slab of a foot or more is likely on lee slopes mainly in the near and above treeline on Sunday. This is most likely on north to east slopes but possible on other aspects. Watch cracking and firmer or chalky wind transported snow. Snow pits may not be helpful due to variability in the snowpack.

New storm slab layers will be likely in areas where there is rapidly accumulating snow for more than a few hours. Warming daytime temperatures may contribute to upside down layers and instability. Pay special attention to slope convexities where storm slab is mostly likely to be triggered.

 Loose wet avalanches may be possible on steep solar slopes on Sunday. Don't overstay your welcome if you start seeing pinwheels or small initial natural loose wet avalanches. Be aware of terrain traps where even a small loose avalanche could have unintended consequences if you venture out on Sunday.

Cornices have grown large recently. Cornices can break much further back on ridges than expected and releases can be unpredictable during the spring.

Although not listed as an avalanche problem, large powerful glide avalanches can release unexpectedly so avoid areas below steep unsupported slopes or rock faces.

Weather and Snowpack

Snow accumulations Wednesday to Friday following the last front varied based on elevation, with only a few inches below 5000 feet and about 8-10 inches at the Mt. Hood Meadows and Timberline stations. 

 The new snow since Monday is generally well-bonded to a moist crust buried March 22nd.  

Frequent March storms have built large cornices along ridges in many areas.

The mid and lower snowpack along the west slopes should generally be a stable mix of crusts and layers of moist and rounded snow crystals.

Recent Observations

The Mt Hood Meadows pro-patrol on Tuesday morning 3/22 found wind loaded pockets of mostly small wind slab 12-18 inches deep in the above tree line which were stubborn to release by skis. On Tuesday afternoon a recent natural cornice release was seen at about 7000 feet on Marmot Ridge which released a small pocket of wind slab.

By Wednesday morning, Meadows pro-patrol found dense wind slab above treeline and on lee slopes only affected by large explosives. Above treeline, satstrugi was widely sculpted into the snow surface with some icy surfaces on windward ridges.

Explosive control in the Meadows ski area on Thursday produced pockets of 1-1.5 wind slab in the near and above treeline.

NWAC pro-observer Laura Green was out in Newton Canyon on Friday and found that winds had plastered the latest snow down with conviction, with moderate compression tests in the new snow and hard compression tests at the 3/22 interface. Limited rollerballs were seen on solar slopes. A size 2 natural avalanche from a potential cornice release was seen in White River Canyon.