Melt freeze on solar aspects and near surface facets on northerly aspects.

Location Name: Johnson Canyon Region: Donner Summit Area Observation Date & Time: Thursday, December 13, 2018 - 12:00
Location: 39.342183, -120.304332 See map: CalTopo	Is this an Avalanche Observation?: No Conditions Alerts: Rapid or Prolonged Warming Rapid or Prolonged Warming›Strong Sunshine Rapid or Prolonged Warming›Warm Temperatures

Observation made by: Forecaster

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Observation

Description of Snow, Weather, and Avalanche Conditions:

Sun vs shade dictated snow surface conditions. Snow surface melt observed in sun exposed areas on E-SE-S aspects. Fist hard near facets holding on NW-N-NE-ENE aspects with either low angle sun or shade. Easy shears within the top 10 cm of the snowpack consistent with the 12/4 surface hoar layer were noted in areas holding near surface facets unaffected by melt. Surface hoar crystals were rather decomposed but still allowed for the easy shear.

Near surface facets on ENE aspect at about 7,200'.

S aspect surface wet snow.

Forming melt freeze surface crust on flat terrain at 7,600'.

Snowpack Details

Persistent Weak Layers:

Buried

Terrain Details

Terrain: elevations:

Near Treeline

Below Treeline

Terrain: aspects:

Weather Details

Elevation of Observation:

6000-7000 ft.

7000 - 8000 ft.

Blowing Snow:

None

Wind Speed:

Calm

Sky Cover:

Clear

Air temperature:

Above Freezing

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Melt freeze on solar aspects and near surface facets on northerly aspects.

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Melt freeze on solar aspects and near surface facets on northerly aspects.

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