Avalanche Forecast
Regions: Mt Hood.
Dangerous avalanche conditions are expected Sunday night and early Monday. The avalanche danger should lower during the day as rainfall comes to an end.
Detailed Forecast
Moderate to heavy rain should reach up into the above treeline elevation band through Monday morning.  Luckily, the rainfall should quickly ease Monday morning although the high snow levels will stick around. Â
This will orient the avalanche type toward wet slab and wet loose on Monday. Rain should quickly load snowfall received earlier in the storm and result in widespread natural loose wet avalanches especially in steeper terrain. Natural wet slabs, mainly on lee aspects near and above treeline, have the potential to be larger and more destructive. Due to low snow cover, the avalanche danger will quickly decrease in the below treeline band at lower elevations.Â
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Snowpack Discussion
On Sunday, light snow along with moderate westerly transport winds accumulated new snow onto lee aspects with rising temperatures leading to inverted new snow layering. Pro-observer C.J. Svela did not find the new snow particularly reactive in White River Canyon around mid-day, but the heaviest warming and precipitation had not occurred yet. Precipitation intensity should increase rapidly Sunday night with quickly rising snow levels.  Rain should reach well into the above treeline elevation band by early Monday morning.  Avalanche concerns for Mt. Hood will be directly related to the incoming storm.  Â
A generally strong mid and lower snowpack is expected at Mt Hood.
Avalanche Problems
Wet Slabs
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 Slab avalanches can be very destructive.
Avoid terrain where and when you suspect Wet Slab avalanche activity. Give yourself a wide safety buffer to handle the uncertainty
A Wet Slab avalanche. In this avalanche, the meltwater pooled above a dusty layer of snow. Note all the smaller wet loose avalanches to either side.
Wet slabs occur when there is liquid water in the snowpack, and can release during the first few days of a warming period. Travel early in the day and avoiding avalanche paths when you see pinwheels, roller balls, loose wet avalanches, and during rain-on-snow events.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2
Loose Wet
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. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. 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.
Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.
Several loose wet avalanches, and lots of pinwheels and roller balls.
Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Very Likely
Expected Size: 1 - 1