THIS AVALANCHE FORECAST EXPIRED ON April 5, 2019 @ 6:58 am
Avalanche Forecast published on April 4, 2019 @ 6:58 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

The avalanche danger remains MODERATE for all elevations. Daytime warming and a weak overnight refreeze make loose wet avalanches an ongoing problem. Some lingering wind slab problems may still exist at the upper elevations. 

2. Moderate

?

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

2. Moderate

?

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

2. Moderate

?

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
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Overall, loose wet activity should be less widespread today than yesterday due to a slightly better (albeit still weak) overnight refreeze and slightly cooler daytime temperatures. However, enough warming may still occur to allow loose wet avalanches to become possible. These could occur on any aspect and elevation where wet snow forms. They could still entrain enough snow to have serious consequences for backcountry travelers especially on steep slopes where they can run longer distances or in areas with terrain traps. 

Maintain awareness of conditions and terrain by looking for signs of wet snow instabilities like ankle deep wet snow, roller balls, pinwheels, and small point releases. These can foreshadow larger loose wet avalanche activity. Once the snow starts to get wet it is time to move to a colder slope or call it a day. 

Avalanche Problem 2: Wind Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Some slabs of wind drifted snow may linger on leeward aspects in terrain above 8500 to 9000 ft where more snow accumulated during the last storm. These wind slabs should be more difficult to trigger today. However, human-triggered avalanches may remain possible in some areas especially in complex or extreme terrain including cliffy areas, couloirs, and unsupported slopes.

Use clues like cornices above a slope, wind drifted snow, ripples in the snow surface, and other wind created textures to determine where wind slabs may linger.

recent observations
Submit Observations

* Numerous loose wet avalanches were reported on Trimmer Peak, in Twin Peaks area, and in the Mt. Rose backcountry yesterday. Many of these were D1 in size and some may have involved enough snow to reach D2 in size especially on longer steep slopes. They occurred on all aspects and involved the new snow and some of the wet snow below the new snow. Natural and human-triggered activity occurred.

* Signs of wind slab instability including test slope cracking and failure and unstable snowpit test results were observed on Chickadee Ridge and Ophir Peak in the Mt. Rose backcountry. These measured up to 14 inches deep and only existed above 9000 ft in this area. 

* The most recent storm snow became wet and sticky on all aspect up to at least 8700 ft before 11 am yesterday. 

Weather and CURRENT CONDITIONS
weather summary

Skies remained partly cloudy during the night and overnight lows stayed above freezing in many places. Temperatures did drop below freezing in areas above 8700 ft. Cloud cover and SW winds should increase today as a small storm system moves into the area. Some precipitation could start this afternoon as rain or snow depending on elevation. Currently, snow levels are forecasted to start around 7000 ft and drop to 6000 ft by tomorrow. This system should only bring a few inches of snow with it. Another system should follow this one on Friday with more snow and wind. 

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 27 to 33 deg. F.
Max. temperature: 32 to 43 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 20 to 30 mph
Maximum ridgetop wind gust: 49 mph
New snowfall: 0 inches
Total snow depth: 114 to 160 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Mostly cloudy. Scattered showers in the afternoon. Snow levels 7000 feet. Chance of precipitation is 50%. Mostly cloudy. Scattered showers. Snow levels below 7000 feet. Chance of precipitation is 50%. Mostly cloudy. Scattered snow showers in the morning, then widespread snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 40 to 46 deg. F. 26 to 31 deg. F. 34 to 40 deg. F.
Mid Slope Winds: Southwest around 15 mph with gusts to 30 mph. Southwest 15 to 20 mph with gusts to 40 mph. Southwest 15 to 25 mph with gusts to 45 mph.
Expected snowfall: up to 1 inch. | SWE = less than 0.10 inch. 80% probability of up to 2 inches. 20% probability of 2 to 4 inches. | SWE = up to 0.15 inch. 70% probability of 1 to 3 inches. 30% probability of 3 to 5 inches. | SWE = up to 0.40 inch.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Mostly cloudy. Widespread snow showers in the afternoon. Snow levels 7000 feet. Chance of precipitation is 60%. Mostly cloudy. Scattered snow showers through the night. Snow levels below 7000 feet. Chance of precipitation is 70%. Mostly cloudy. Scattered snow showers in the morning, then widespread snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 33 to 41 deg. F. 23 to 28 deg. F. 28 to 34 deg. F.
Ridge Top Winds: Southwest 15 to 25 mph with gusts to 45 mph. Southwest 15 to 30 mph with gusts to 50 mph. Southwest 20 to 30 mph increasing to 30 to 45 mph in the afternoon. Gusts up to 70 mph.
Expected snowfall: up to 2 inches. | SWE = less than 0.20 inch. 80% probability 1 to 3 inches. 20% probability of 3 to 5 inches. | SWE = up to 0.20 inch. 70% probability of 2 to 4 inches. 30% probability of 4 to 6 inches. | SWE = 0.15-0.40 inch.
Disclaimer

This avalanche forecast is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This forecast 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 forecast applies only to backcountry areas outside established ski area boundaries. This forecast describes general avalanche conditions and local variations always occur. This forecast expires 24 hours after the posted time unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the avalanche forecast call (530) 587-3558 x258