THIS AVALANCHE ADVISORY EXPIRED ON April 5, 2016 @ 6:48 am
Avalanche Advisory published on April 4, 2016 @ 6:48 am
Issued by Brandon Schwartz - Tahoe National Forest

MODERATE avalanche danger will exist this morning and continue through the afternoon hours for all elevations and aspects on slope 35 degrees and steeper due to loose wet avalanche problems. Cloud cover last night is expected to have kept overnight snow surface refreeze from occurring in many areas. A period of LOW avalanche danger with supportable snow surface conditions may not exist this morning. A possible wet slab avalanche occurred yesterday in the Mount Rose area. Details are limited.

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Air temperatures were in the mid 30s to upper 40s last night in the 6,500' to 9,500' elevation range. Cloud cover is expected to have inhibited or greatly reduced the amount of snow surface refreeze that usually occurs from radiational cooling. As a result, a poor overnight snow surface refreeze is expected to have occurred last night in many areas. In areas where some amount of snow surface refreeze did occur it may be deceptively superficial, turning unsupportable and potentially unstable prior to the mid morning hours.

Areas that did not refreeze will be easy to identify this morning. In areas where some amount of snow surface refreeze did occur, kick boots through the surface crust to assess thickness. Beware of areas of crust less than 3 inches thick. In direct sun exposed areas that thickness of crust will provide only a very short window of supportable conditions before melting away and exposing deeper wet snow below and potential loose wet avalanche problems.

recent observations

A report was received yesterday evening of a potential wet slab avalanche that occurred around 2 pm on the Fireplug, aka The Diamond feature adjacent to the Mount Rose Highway. Details are limited at this time and more will be known after a visit to the site today. The slope where the avalanche occurred is a SE aspect near treeline. The avalanche started at around 9,000' and ran for about 300 vertical feet. The avalanche was large enough to bury or injure a person.

Observations made yesterday on the north side of Carson Pass on the SW flanks of Red Lake Peak revealed that a decent snow surface refreeze had occurred Saturday night in open areas and a poor refreeze had occurred in treed areas. Snow surface conditions in open areas remained supportable through the morning hours with the first signs of the transition to unsupportable wet snow observed on a S aspect at 8,700' at 11:15 am. The high sun angle of April was noted to allow for surface melt-freeze conditions to occur on steep N-NE aspect terrain at 9,600'.

 

Weather and CURRENT CONDITIONS
weather summary

A weather system passing to the north of the forecast area is spreading high level cloud cover over the region. Ridgetop winds are increasing out of the SW this morning and are moderate in speed. Precipitation is not expected today, but an isolated shower cannot be ruled out, especially over the far souther portion of the forecast area this afternoon. Snow level would be around 9,000'. Ridgetop winds are forecast to shift to the NE tomorrow. Air temperatures will cool a couple of degrees tomorrow in response to the NE flow, but will remain above average.

 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 33 to 39 deg. F.
Max. temperature in the last 24 hours: 47 to 53 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 19 mph
Maximum wind gust in the last 24 hours: 36 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 70 to 113 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Partly cloudy skies. Partly cloudy skies. Sunny skies.
Temperatures: 53 to 61 deg. F. 23 to 30 deg. F. 51 to 57 deg. F.
Wind Direction: W SW E
Wind Speed: 10 to 15 mph 10 to 15 mph 10 to 15 mph
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Partly cloudy skies. Partly cloudy skies. Sunny skies.
Temperatures: 44 to 54 deg. F. 23 to 30 deg. F. 46 to 52 deg. F.
Wind Direction: W W to NW NE
Wind Speed: 15 to 20 mph with gusts to 35 mph. 20 to 25 mph with gusts to 40 mph, decreasing to 10 to 15 mph with gusts to 25 mph after midnight. 15 to 20 mph with gusts to 30 mph.
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory covers the Central Sierra Nevada Mountains between Yuba Pass on the north and Ebbetts Pass on the south. Click here for a map of the forecast area. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258