Wet snow

/Wet snow
Wet snow 2017-10-20T13:20:17+00:00

Liquid water due to melt or rain weakens the snowpack and may cause wet snow avalanches. They generally release naturally and are seldom triggered by skiers or boarders.

Tactics: good timing and trip planning. Wait until good refreeze.

Duration: hours to days

Typical signs:

  • Overcast skies
  • High temperatures /strong solar radiation
  • Weak night refreeze
  • Deep sinking
  • Onset of rain, snowballing, pin wheeling and small wet slabs or loose wet
    avalanches

Typical distribution:

  • When sun is the main cause, distribution is mostly depending on aspect and elevation. Aspect and elevation change along the season. Avalanches often start near dark spots
  • All aspects are affected in the event of rain on snow.

Tips:

  • Start early, finnish early
  • Wait until having good night refreeze
  • Consider avalanche runout zones and the possibility of big natural avalanches

Typical Wet Snow Avalanche Situation

  • Rain or melt water flowing into a dry snowpack leading to marked weakening at layer boundaries (rain in midwinter, first heavy melt phase of the snowpack due to solar radiation in March).
  • Loss of strength through uniform wetting of the snowpack. Collapse of weakened base layers (spring).

If the snow surface is distinctly refrozen, following a clear night, mostly favourable conditions prevail before midday. Pay attention after midday and generally at any time when the sky is overcast. Pay attention to diurnal variation!

Rain

  • Warm front creates a typical wet avalanche problem. Initial snow limit is low but usually increases with the arrival of the warm air, and rain on new snow.
  • Rain in spring on an isothermal snowpack is usually less effective.

Temperature

  • Take into account previous and expected variations. Cold temperatures prolong the danger. Warm temperatures have a long term stabilizing effect. Particularly repeated warming and cooling cycles.
  • Rapid, distinct warming towards 0°C increases instability. Solar radiation significantly warms the surface layers, thereby promoting instability.

Uso de cookies

Este sitio web utiliza cookies para que usted tenga la mejor experiencia de usuario. Si continúa navegando está dando su consentimiento para la aceptación de las mencionadas cookies y la aceptación de nuestra política de cookies, pinche el enlace para mayor información. ACEPTAR

Aviso de cookies