Mt Hood

Problèmes avalancheux

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Possible

  Taille

  1–1.5

  Temperatures continue to climb on Mt Hood and recent dry snow remains susceptible to strong April sunshine as freezing levels approach the top of the volcano. The risk of wet loose avalanches may expand on shaded aspects and into upper elevation terrain. The nature of the wet avalanche activity likely differs with altitude. At the highest elevations, chunks of snow falling off steep, cliffy terrain represent a hazard in their own right, but can also entrain moist snow on the slopes below. Exposed ridgelines likely developed large cornices during the last storm cycle that could fail without warning. At lower and middle elevations, a thin crust likely formed on the snow surface by Saturday above around a foot of recent dry snow. As the crusts break down, the snow in more sheltered terrain may become moist and heavy. Expect the potential for rollerballs, and generally small wet loose avalanches  on slopes steeper than 35 degrees. NW and NE aspects that were recently shaded are starting to experience sunshine as we head later into the spring. Don't discount the potential for these aspects to start producing avalanches if previously dry snow becomes sticky and gloppy.

  Reduce your exposure to steep slopes which may be above you during this time of rapid transition. Avalanches are likely to slide efficiently atop the 3/31 crust. Although they may start slowly, they can gain steam and mass quickly as they head down the slope.

  

• 

  Wind Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpin
  • Limite forestière
  • Sous la limite forestière

  Probabilité

  Unlikely

  Taille

  1–2.5

  Mt Hood Meadows Pro Patrol triggered wind slabs each of the last 3 days with the largest slab (size 2.5) triggered early Friday, following the most intense winds of the storm cycle on Thursday. The most recent slab development is less than 2 days old, but we expect these  hard slabs will be very stubborn to trigger by Saturday. Most of the slab reactivity was in the 6000-7000 ft range and failed on a hand hardness change on top of the 4/1 interface (a few inches above the 3/31 crust). Extreme winds rendering the highest elevation snow mostly unreactive while sunshine and warm temperatures have likely accomplished a similar task at lower elevations and on sun-affected slopes. Given the potential size of the avalanches, you're well served to steer around steep, heavily wind loaded terrain at middle and upper elevations on shaded or E aspects. Slabs could exist well below ridgelines. With many slopes scoured back to the 3/31 crust, it should be possible to identify areas of wind drifted snow. Steer around the edges of these wind deposits. In some cases, you may find intensely mottled sastrugi (wind scour), which should be unreactive to human trigger, but may not make for good riding. If you choose to engage with more consequential terrain on wind loaded aspects, it's worth evaluating the 4/1 interface and the firm slab it supports on a test slope before committing. It's worth noting that although these slabs are unlikely to be triggered by humans, a large cornice fall could be the impetus for one to wake up.