Avalanche forecast

Mt Hood

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
No rating
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Highlights

Dynamic conditions - strong wind and warming - adds uncertainty to a prolonged storm cycle. Natural avalanches are possible, potentially originating on the upper mountain. Avoid steep slopes where you can trigger a dry or wet snow avalanche and reduce overhead exposure on Monday.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    The changeover from snow to rain brings with it a shift from dry avalanche problems to rapidly developing wet loose hazard. You can trigger a large avalanche on a steep slope, or an isolated natural avalanche could descend from connected terrain, including the upper mountain. Peak hazard typically lasts for a brief period of time, so add a safety margin, and always maintain safe return routes. With all the new snow and some uncertainty regarding the sensitivity of that new snow to wet avalanche trigger, it's a good time to give some extra margin around steep, open slopes.

    Example: A large wet loose avalanche.

    Photo: Joe Dellaporta

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    Before the transition from snow to rain, heavy snowfall and strong winds will continue to load the same slopes where it has been accumulating all weekend. Snow drifts will be deep, wide, and difficult to identify in the blizzard. Keep it simple and stay off of actively wind loading slopes steeper than 35 degrees.

    Example: Drifts and blowing snow along Pea Gravel Ridge. 

    Photo: Joe Dellaporta

Avalanche Discussion

Mt Hood has been absorbing a lot of water this week, and that trend continues for the foreseable future. 3-4" of largely liquid pricipitation hit the slopes of Mt Hood Friday night with that rain reaching at least 7,3000 ft, but likley closer to 9,000 or 10,000 ft. Temperatures dropped Friday evening, burying the 12/5 crust with heavy, wet, dense snow down. Snowfall was limited at ski area bases (3-5"), but expect significantly more above 6000 ft.  A warming trend recommenced on Sunday, likely forming another crust up to 6000 ft or so.

We haven't seen upper elevation terrain since the middle of last week, so our uncertainty regarding the snowpack is quite high. Of particularly interest to us is the 12/5 crust. Without any knowledge of that crust, we can't rule out a slight possibility of water pooling above the crust and producing isolated wet slab avalanches during this extended atmospheric river event.  Wet slabs are difficult to escape, but the terrain management during this storm cycle should be the same avoidance strategy you use with wet loose avalanches.

Joe Dellaporta visited the south side of Mt Hood during a recent weather window on Wednesday. The new snow likely expanded snow coverage since his tour, but recent gains may face more losses at lower and middle elevations as snow rise into the upper elevations on Monday. In general, snow coverage increases drastically from around 6000-7000 ft, but thanks to prevailing wind patters, lee slopes have plenty of snow for avalanches at above 5500-6000 ft.

These unrelenting WSW winds continue to strip wind-ward slopes and ridgelines, limiting some of your typical safe downhill routes to boot travel. If you don't have a safer low-angled descent route with enough snow to ride, there's no shame in walking back down your safer ascent route. Remember it's a long winter season in the PNW.

With the warm start to the 25-26 winter season, we have less snowpack information than usual to start daily forecast operations. For zones and elevation bands with less snow than needed for avalanche hazard, we will issue a forecast with No Rating. Anticipated avalanche and weather conditions will still be updated daily. NWAC will issue an avalanche danger rating for a zone when enough snow to produce avalanches has accumulated at middle and upper elevations.

Regions covered