Central Sierra Nevada

Problemi valanghivi

• 

  Storm Slabs

  N

  NE

  E

  SE

  S

  SW

  W

  NW

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco

  Probabilità

  Likely

  Dimensione

  1.5–2.5

  We are on the tail end of HIGH danger transitioning to CONSIDERABLE danger today. What does that mean? We expect the chances for natural avalanches to decrease once the period of high intensity snowfall this morning comes to an end. At the same time, the chance of a skier, snowboarder, or snowmobiler triggering an avalanche remains elevated all day long.

  Today's storm slab avalanche problem applies to all avalanche terrain. The potential remains for large avalanches to occur in wind protected areas, in addition to the common wind loaded terrain. Any visible clues to snowpack instability should be used as reasons not to venture into avalanche terrain. If you see any sign of recent avalanches, snow surface cracking, or blowing and drifting snow in your area of travel, the chances of triggering an avalanche are increased. Simply choosing to avoid avalanche terrain today is a good call. There will be days ahead when travel in avalanche terrain has a wider margin of safety.

  At least one storm slab avalanche was triggered yesterday by a solo backcountry traveler who was caught, carried, and partially buried in an area of well defined avalanche terrain. Storm slabs have increased in depth and extent across terrain over the past 24 hours as high intensity snowfall continued into this morning. Wind loaded areas should produce the largest avalanches today, as wind drifted snow has filled in very rapidly onto slopes along the downwind side of ridgetops and into gully features. High intensity snowfall also tends to produce instability within the new snow in wind protected areas, as new snow accumulates faster than it can stabilize. There was another period of warming air temperatures around 9-11 pm last night. This warming may have added a density change weak layer into the storm snow that could further contribute to snowpack instability today.