Bulletin d’avalanche

Mt Hood

Northwest Avalanche Center
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Danger d’avalanche

Wed
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Strong wind speeds and new snow will create very dangerous avalanche conditions near and above treeline. Tuesday will be a good day to avoid all leeward slopes that show signs of fresh wind drifting.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1.5–2.5

    New snowfall and radical wind speeds will build large slabs of wind-drifted snow. These may be easily triggered by the weight of a human or even avalanche naturally. Tuesday will be a good day to give these areas a wide buffer.

    Due to high wind speeds, you may find these slabs forming in unusual areas, such as well below treeline and further down slope than usual. You’ll also find them forming under cornices, on the leeward side of ridges, and scattered through the alpine. However, it won’t be the day to search these things out. Use visual clues to help you avoid slopes of concern. Look for where the wind is blowing snow, sharp cornices forming, or pockets that look rounded or pillow-like. These are all indicators of wind slabs forming near-by. If you notice shooting cracks, take a big step back and avoid any nearby steep terrain. 

     

    (1/17/2023)

    Shooting crack in wind drifted snow - a red flag that should not be ignored.  Avoid wind loaded slopes if you notice signs like this. 

    Photo: Joe Dellaporta

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–1.5

    As new snow piles,  it may be easy for you to  trigger small avalanches in more sheltered locations within the storm snow .  These storm slabs will likely be most sensitive during the early morning hours corresponding with the heaviest precipitation rates. Use small test slopes or hand pits to look at how the new snow reacts to your weight. If you notice cracks shooting out or snow sliding easily on test slopes, give steep slopes a wide buffer.

    (12/20/2022)

    You may be able to trigger small storm slab avalanches like this, even in those more sheltered areas below treeline. You just need a slope steep enough. 

    Photo: Alexa Cathcart

Avalanche Discussion

Avalanche Accident Colchuck Pk, East Central Zone

We’ve received preliminary information of an avalanche incident on Colchuck Peak, SW of Leavenworth, WA. (East Central Zone) The accident occurred on Sunday, February 19 and involved a group of 6 backcountry travelers. Three members of the group are suspected to have been buried and perished in the event. Another sustained injuries and was evacuated by SAR.  Rescue efforts are ongoing. NWAC is working with Chelan County Sheriff’s office and will make updates as more information becomes available.

 Forecast Discussion:

Mt Hood is in for a wild ride over the next 24 hours. We’re looking at a good amount of precipitation paired with very strong wind speeds. This combination will make for very dangerous avalanche conditions at mid and upper elevations. 

The messaging is simple- just avoid all areas where an avalanche can start, run,or stop. It won’t be the day to thread the needle, so increase your safety margins by sticking to low angle, sheltered slopes and give those steeper (possibly tempting looking)  larger slopes a wide buffer. 

New snow will be falling on a mixed bag of surfaces. Observers have been reporting moist snow on solar slopes, a freezing rain crust that may extend to 6000 ft, and soft preserved snow on shaded aspects. So as new snow piles up, be sure to dig down to check how the new snow is acting with the old snow surface. 

On Friday,  I traveled into the Gunsight Ridge area to track possible weak surfaces on shaded aspects before heading into this active weather patter. Due to high wind speeds, I didn't find much in the form of surface hoar or near-surface facets. That being said,  it doesn't mean it does not exist in other areas, so keep an eye out as new snow starts trickling in. What caught my eye was a sneaky layer of buried surface hoar about 17 inches below the snow surface. I haven't seen this layer in other areas on the mountain, but it's something worth highlighting if you travel along these ridges in the Bennett Pass or Pocket Creek areas. 

If you get out, let us know what you see by submitting a public observation.

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