Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Wet avalanches should still be on your radar anywhere the surface crust breaks down into wet, saturated snow. If you encounter these conditions, stay out of and away from extreme terrain features. Expect a variety of surface conditions including, chalky wind-textured snow,  firm icy surfaces, and corn or mushy snow.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–1.5

    Monday will be sunnier and perhaps warmer than Sunday. Expect a shallow overnight refreeze to break down under direct sunshine. Once this occurs, you could trigger a generally small wet avalanche. Although the snowpack has settled into the warmer weather pattern for one more day, the strong sunshine could increase the danger slightly relative to Sunday. Wet avalanches remain relatively unlikely, but if you find yourself punching into wet snow past your ankle, anticipate that the danger may be elevated in your terrain. Wet avalanches can initiate when you push snow downhill and it entrains more snow as it moves, or it could also release as rocks warm up and drooping cornices collapse in more open terrain at higher elevations.  If the crusts are sufficiently thick and supportive, you might encounter high quality riding as the crust softens into "corn."

    Small wet loose avalanches and rollerballs in very steep terrain of the Polallie Headwall that likely released midweek. 

    This is the sort of terrain you could get into trouble with quickly even with a small avalanche. 

    Photo: Ryan Matz

Avalanche Discussion

March 2nd is expected to be the 6th dry day at Mt Hood since the stormy pattern ended last Tuesday and it will feel very spring-like on Mt Hood. Heading into last weekend, wind and sun blasted the mountain.  NPS Climbing Rangers found that the widespread rain crust formed on Tuesday had eroded from the persistent westerly winds above 7000' while traveling on the NE side of the mountain.  The upper mountain was highly variable, a mix of chalky, wind-textured snow and firm, icy-scoured surfaces.  On sun-exposed aspects,  surface crusts generally exist to above NWAC forecast elevations. A surficial rain crust at lower and middle elevations softened and in some cases broke down on Saturday, leading to rollerballs and small wet loose avalanches, but clouds largely prevented this on Sunday. Sunday's sunnier weather increases the chances of the crust breaking down relative to Sunday.

The last storm cycle produced small to large natural slab avalanches at upper elevations (D2.5 in the gallery below) that likely ran during peak storm intensity.  These slabs are likely to be unreactive at this point. Mt Hood Meadows Pro Patrol tested wind-loaded terrain in their upper bowls on Thursday with explosives and did not produce any new avalanches of note.

If you're traveling to the north or east side of the mountain, continue to travel more cautiously, where less is known about the weaker/shallower snowpack.  A well-documented weak layer/crust interface has become a persistent slab avalanche problem just to our north, with scary avalanches triggered in the West South zone recently. Last Sunday, forecaster Joe Dellaporta found that this weak layer exists in northeastern locations of Mt Hood, including near Tilly Jane and Cloud Cap (observation here). This weak layer showed the ability to propagate during snowpack tests.  NPS Climbing Rangers found this weak layer interface in a nearby area on Friday, with indicators that the snowpack may be healing over time (see gallery below).  While this layer was easy to identify here, it wasn't as obvious on the south side of the mountain, where the snowpack was generally deeper and stronger over this crust. 

The mountain is looking much more winter-like after the last few storms.  That said, continue to use caution at lower elevations and on thin-coverage aspects.  Allow extra time for stream crossings,  open holes in the snow,  etc in areas with a thin snowpack. 

 Let us know what you see by submitting an observation here or on the AvyApp

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