Avalanche forecast

Mt Hood

Northwest Avalanche Center
View on map

Avalanche danger

Sat
Alpine
1 · Low
Treeline
2 · Moderate
Below
2 · Moderate
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A slab down 1-2 ft continues to produce reactive results in the Mt. Hood area for those traveling below and near treeline. Continue to limit your exposure to large, open slopes even as shallow as 30 degrees in order to maintain a margin of safety. During these unusual conditions, travel will be generally safer above treeline where you can navigate around very shallow wind slabs.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Our persistent surface hoar layer remains reactive and like its namesake - persistent. Continue to avoid slopes steeper than 30 degrees until we gain confidence that this problem is behind us. This interface was buried on 12/8 with over 2' of storm snow falling over several days.  After some settlement, if you can still find these layers, they are likely 1-2' down near or below treeline.   

    NWAC forecaster Joe Dellaporta traveled in a shallower snowpack in the Tilly Jane area. He found reactive tests failing on the surface hoar layer 12-15" in 4/5 pits in the below and near treeline elevation bands. In most areas of Mt. Hood you will find a thin gray line 1-2 ft down. The consistent reactivity in test results suggests that human-triggered avalanches remain possible. While you're likelihood of triggering an avalanche on a 30-35 degree slope continues to edge downward, caution remains prudent. If you do choose to ease into avalanche terrain, make sure you conduct a thorough snowpack evaluation (multiple ECT or shovel tilt test) in the local terrain.

    Previously, shooting cracks were observed in White River Canyon on Monday. The last known avalanches on these layers occurred on Sunday when we received numerous public observations (thank you for submitting!) that reported widely propagating slab avalanches as well as snowpack test results highlighting this layer.  Most significantly, a skier was caught, carried and partially buried after being strained through trees that day. Fortunately, the skier was uninjured and self-extracted.

     

    4/5 test pits produced fully propagating results in extended column tests.  All of which failed on the same layer of buried surface hoar (SH).  Generally this SH was found below and near treeline in the Tilly Jane area. 

    ECTP14 30 cm down on 4mm SH.  Photo: Joe Dellaporta

Avalanche Discussion

Persistent slab avalanches can be killers and stick around longer than other avalanche problems. They can break widely across slopes, around terrain features and can be triggered from much lower angled terrain below.  Until we can put this problem to bed with more confidence, you'll need to continuously assess this layer as you travel throughout the landscape.  Look and listen for red-flag indicators like whumpfs or rolling collapses. While a snowpack test won't give you a green light, you can use snowpack tests to gain information and help rule out terrain.  Check out the video for more info. 

Winds ticked upward into the 20-30 mph range. It has formed very shallow slabs on the south side of Mt. Hood. At this point, exposed slopes have limited snow left to transport and older slabs have become unreactive. While conditions are generally far safer above treeline, maintain an awareness for active and recent snow transport and steer away from a steep, freshly loaded slope.

Sunshine and slightly milder temperatures have allowed sun crusts to form during the work week.  You may see a few rollerballs on steep sunny slopes as well, but wet loose avalanches are unlikely.  

If you get out into the backcountry,  please submit an observation on our public observation platform!  These observations play an integral role in producing a quality avalanche forecast, but also help the greater backcountry community.

Regions covered