Avalanche Advisory: Sunday - Mar 3, 2019

THIS AVALANCHE ADVISORY EXPIRED ON March 4, 2019 @ 6:37 am
Avalanche Advisory published on March 3, 2019 @ 6:37 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

1-2ft of heavy snow fell between Friday night and Saturday afternoon with strong SW winds. CONSIDERABLE avalanche danger will remain at mid to upper elevations thru today as moderate SW winds continue to load slopes.  Sensitive wind slabs, lingering storm slabs, and possible loose-wet activity are the main concerns. 

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.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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New snow and strong SW winds formed sensitive wind slabs yesterday.  A cornice collapse yesterday in the Sherwins triggered a 200-300’ wide avalanche which ran thru the trees.  Continued moderate SW winds today will continue to build sensitive slabs.  Be on the lookout for denser wind deposited snow particularly on the leeward side of ridgelines, sidewalls of gullies and around other features that promote drifting. Carefully evaluate the snow and use cautious routes to avoid being on or under potentially sensitive wind deposited slopes.  Give ridgeline travel healthy respect, as cornices can break much further back from the edge than you’d expect.  An avalanche could certainly be large enough to burry you today.  

Avalanche Problem 2: Storm Slab
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Yesterday’s warm storm came in upside-down, with less dense snow at the bottom.  Storm slabs in sheltered areas generally stabilize quickly, but with this poor structure storm slabs may still remain sensitive today. Be particularly cautious of steep convex rolls.  Do your own localized assessments before committing to steep terrain.

Avalanche Problem 3: Loose Wet
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If the sun comes out today, watch out for loose wet activity on solar aspects, beginning with east slopes in the morning, thru south and west slopes in the afternoon.  With the new snowfall, small point releases starting near rock bands could entrain enough snow to sweep a rider off their feet for a violent ride, especially in the confines of a gully or couloir. Be aware of what is above you!  Winds today could help negate some of this warming threat.  

advisory discussion

Old rain, melt-freeze, and firm wind board crusts continue to make travel challenging in areas with shallow overlying snow deposits.  Shallow deposits can be due to wind-stripping and in steeper areas where sloughing and prior avalanching have occurred.  Besides challenging travel, because new snow may not stick as well to these areas, they may be more prone to sloughing and avalanching today.  *Crampons and ice ax or whippet are prudent tools to carry.

recent observations
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-3/2 - Mammoth - Sherwins: Skier triggered cornice drop resulting in wide avalanche.

-3/2 - Mammoth - Sherwins: Sensitive avalanche conditions, poop chute avalanche.

-3/2 - June Area:  Intense snowfall and rollerballs.

Weather and CURRENT CONDITIONS
weather summary

Expect partly cloudy skies and perhaps some sunshine with chances of minor snow showers through today and tonight with mild temperatures reaching near freezing around 10,000’. Light to moderate SW winds should continue with gusts into the 50s at mid to upper elevations through tomorrow. 

Sunny skies are likely for tomorrow before another significant warm Atmospheric River is likely to drop 1-3’ of snow for higher elevations Tuesday thru Wednesday. Unsettled weather remains on-tap thru the end of the week with colder temperatures. 

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: Partly cloudy. Chance of snow in the morning, then chance of snow showers in the afternoon. Snow levels 7000 feet. Chance of precipitation is 35%. Partly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 30%. Sunny.
Temperatures: 32 to 40. deg. F. 19 to 24. deg. F. 35 to 43. deg. F.
Mid Slope Winds: Southwest around 15 mph with gusts to 50 mph. Southwest around 15 mph with gusts to 45 mph. Southwest around 15 mph with gusts to 40 mph.
Expected snowfall: up to 3 inches. | SWE = less than 0.10 inch. in. up to 2 inches. | SWE = less than 0.10 inch. in. 0 in.
Over 10,000 ft.
Sunday Sunday Night Monday
Weather: Mostly cloudy then becoming partly cloudy. Chance of snow in the morning, then chance of snow showers in the afternoon. Snow levels 7000 feet. Chance of precipitation is 40%. Mostly cloudy then becoming partly cloudy. Chance of snow showers through the night. Snow levels below 7000 feet. Chance of precipitation is 40%. Partly cloudy then becoming sunny.
Temperatures: 24 to 30. deg. F. 14 to 19. deg. F. 28 to 34. deg. F.
Ridge Top Winds: Southwest 25 to 35 mph with gusts to 55 mph. Southwest 20 to 35 mph with gusts to 50 mph. Southwest 20 to 35 mph with gusts to 50 mph.
Expected snowfall: up to 2 inches. | SWE = less than 0.10 inch. in. up to 2 inches. | SWE = less than 0.10 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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