Avalanche Advisory: Sunday - Mar 1, 2020

THIS AVALANCHE ADVISORY EXPIRED ON March 2, 2020 @ 6:51 am
Avalanche Advisory published on March 1, 2020 @ 6:51 am
Issued by Chris Engelhardt - Eastern Sierra Avalanche Center

CONSIDERABLE avalanche danger exists at all Elevations. With 7” of new snow as of 0630am and still accumulating evaluate for Wind slab, Storm Slab and other new snow instabilities such as Loose Dry sloughing. ALL ASPECTS could present hazard today as Strong W-SW winds will transition to more NW-N winds building Wind slab on a variety of terrain features. Careful route-finding and conservative decision making are essential today. Be prepared for frigid temperatures and negative wind chill conditions.

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Very fresh wind slab just deposited in the early morning hours Sunday will be sensitive and likely triggered by a skier. Natural avalanches will also be possible with new snow being deposited on a variety of slick firm surfaces as well as loose faceted areas in the trees. Northerly–Easterly aspects will be of most concern, but ALL ASPECTS should be taken into account due to cross-loading wind effects and predicted changes for wind direction today with winds realigning to a Northerly flow. Identify fat looking pillows of snow and be particularly weary of new cornice development, areas adjacent to ridgeline, gullies, and terrain adjacent to rock bands and collection zones. Take time to communicate with your partners, develop a good plan, be ready to adjust and change your route, and don’t let powder fever override good judgment. Be aware of the terrain above you and if you could be impacted by natural activity from above. Natural avalanche activity is certainly possible today.

Avalanche Problem 2: Storm Slab
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Today’s fresh snowfall with rapid deposition rates will not have much time to settle and bond before eager folks get out riding. Even where not dramatically wind affected, new snow in the form of storm slab may be sensitive to human triggers on a VARIETY OF ASPECTS today. Be cognizant of the previous thin conditions and buried obstacles and avoid riding over terrain traps and unsupported slopes. Even a small slide with could be quite hazardous today.

Avalanche Problem 3: Loose Dry
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Cold temperatures and rapid loading in the early morning hours of Sunday will present LOOSE unconsolidated new snow conditions in many of the more sheltered and wind protected zones. ALL ASPECTS should be considered. Again, the snow will have very little time to settle and bond before riders start to venture in the mountains. Be wary of tight and confined areas or unsupported slopes above cliffs where even a small slough may drag you into or over something nasty.

advisory discussion

Snow Totals as of 630am Sunday March 01.

Virginia Lakes 9409ft =1-2"

Agnew Pass near Tuolumne Meadows 9355ft= ~9"

June Mountain weather plot 9148ft= ~2"

Mammoth Pass near Mammoth Lakes  9500ft= 8.5"

Rock Creek 9600ft=2"

Sawmill near Big Pine/Bishop area 11919ft=4"

recent observations
Submit Snowpack Observations
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2/28 – VA Lakes –snow conditions

2/27 – Mammoth Lakes Basin –George Lk Ridge snow profile

2/27 – Buttermilk Country – Mt Locke – variable surface conditions

Weather and CURRENT CONDITIONS
weather summary

Snow has returned to the Eastside. Intense snowfall started after midnight and continued through Sunday morning with strong SW winds and cold temperatures. Sunday looks to be a stormy day with snow slated to continue through early afternoon with possibly another 5” throughout the day. Winds are predicted to orient towards the NW- North by the end of the day averaging 15-30mph with gusts up to 45mph in the higher elevations. Temperatures will be cold from 11-17F above 10000ft and reaching the mid 20Fs in the lower mountain terrain. Strong to extreme NE-E winds will follow the exit of the system Sunday night into Monday with sunnier skiers developing for the start of the week.

 

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Sunday Sunday Night Monday
Weather: Mostly cloudy. Snow showers likely in the morning, then snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 85%. Mostly cloudy. Chance of snow showers through the night. Snow levels below 7000 feet. Chance of precipitation is 30%. Partly cloudy then becoming sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 18 to 26. deg. F. 7 to 13. deg. F. 26 to 34. deg. F.
Mid Slope Winds: Northwest 15 to 25 mph with gusts to 45 mph. North 15 to 25 mph. Gusts up to 60 mph decreasing to 45 mph after midnight. North 15 to 20 mph with gusts to 65 mph.
Expected snowfall: 80% probability of 2 to 6 inches. 20% probability of 3 to 8 inches. | SWE = 0.15-0.35 inch. in. 60% probability up to 2 inches. 40% no accumulation. | SWE = less than 0.10 inch. in. 0 in.
Over 10,000 ft.
Sunday Sunday Night Monday
Weather: Cloudy. Snow showers likely in the morning, then snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 85%. Mostly cloudy. Chance of snow showers through the night. Snow levels below 7000 feet. Chance of precipitation is 30%. Partly cloudy then becoming sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 11 to 17. deg. F. 2 to 7. deg. F. 18 to 26. deg. F.
Ridge Top Winds: Northwest 15 to 30 mph with gusts to 45 mph. North 25 to 40 mph. Gusts up to 85 mph decreasing to 60 mph after midnight. Northeast 35 to 50 mph becoming north 20 to 35 mph in the afternoon. Gusts up to 75 mph.
Expected snowfall: 80% probability of 2 to 6 inches. 20% probability of 4 to 8 inches. | SWE = 0.20-0.40 inch. in. 60% probability up to 3 inches. | SWE = up to 0.15 inch. in. 0 in.
Disclaimer
This Avalanche Advisory is designed to generally describe avalanche conditions where local variations always occur. This product only applies to backcountry areas located outside established ski area boundaries. The information in this Avalanche Advisory is provided by the Eastern Sierra Avalanche Center, who is solely responsible for its content.

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