Central Sierra Nevada

Avalanche problems

• 

  Loose Wet

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alpine
  • Treeline
  • Below treeline

  Likelihood

  Possible

  Size

  1–2

  Snow conditions can go from crusty to mushy, or from dry to wet, in a very short time; sometimes it may take only an hour (or less) of sun on a slope. Look for these changes as you travel. Once the snow starts to feel wet, heavy, or mushy, or you start sinking up to your boot-tops in wet snow, it's time to move away from avalanche terrain or to a colder area. Roller balls, pinwheels, and small sluffs of wet loose snow can also indicate that larger wet loose avalanches may soon occur. 

  Strong April sun and warmer temperatures today will quickly melt through surface crusts and turn any lingering cold, dry surface snow into warm, wet snow. This layer of wet surface snow will deepen and spread to multiple aspects as the day warms. Slopes with the most sun-exposure will have the most wet snow. Wet loose avalanches will become possible. Some wet loose avalanches may be small, and others may be large, especially on long, steep slopes, where these avalanches can entrain more snow as they move downhill. Keep in mind that even small avalanches can have increased consequences in exposed terrain or if they push you into barely covered obstacles. 

  While most slab avalanches should remain unlikely today, rapid warming might mean that triggering a wind slab on an isolated terrain feature is not impossible. If this does happen, it would likely start entraining wet snow and transition into more of a wet-snow problem as it moves downhill.