Avalanche Advisory: Thursday - Mar 7, 2019

THIS AVALANCHE ADVISORY EXPIRED ON March 8, 2019 @ 6:40 am
Avalanche Advisory published on March 7, 2019 @ 6:40 am
Issued by Chris Engelhardt - Eastern Sierra Avalanche Center

The avalanche danger is CONSIDERABLE at Upper and Middle elevations. MODERATE avalanche danger resides at lower elevations. 18” of heavy snow with locally higher totals has accumulated the past two days. SW winds, new (high water content) snow and continued light (1-6”) snowfall through the day/night will contribute to fresh WIND SLAB and STORM SLAB conditions in the mountains.

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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SW WINDS will persist, blowing and transporting snow across the mountain range. Velocities of 35-50mph will impact the high elevations with the Mid/Low elevations seeing optimal loading speeds of 15-20mph. These winds and heaps of fresh snow available for transport will contribute to fresh deposition on leeward NORTHERLY-EASTERLY slopes. In addition, there were extreme winds over 100mph up high yesterday that will have produced erratic loading patterns in upper/mid elevation bands. Be on the lookout for looming cornices, fat looking wind drifts, pillows, and terrain features conducive to wind loading such as gullies, leeward cirques and cliff bands. Recent avalanche activity, shooting cracks and active snow transport/wind loading are key red flags to keep in mind.

Avalanche Problem 2: Storm Slab
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1-2ft of new snow has fallen across the forecast area the past two days. The snow has high Snow Water Equivalent (SWE) with over 2” of water present in the new storm snow. This thick heavy blanket of snow, although fairly wet and eager to bond to old snow surfaces, will need time to adjust and settle. Confirmation of unstable storm/wind slabs was highlighted by a SKIER TRIGGERED AVALANCHE in the Bardini chutes yesterday. Elevate your awareness in terrain over 35deg for  storm slab in sheltered areas. Avoid travelling on or near convex terrain features, unsupported slopes, and slopes above terrain traps. Cautious route finding both up and down is essential following this last big storm event.

Avalanche Problem 3: Loose Dry
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If venturing into steeper and committing terrain be aware of potential for loose, unconsolidated sloughs that will be easy to initiate with ski turns. Even a small amount of loose snow moving in confined terrain can take a rider for a nasty ride if you get your feet taken out from under you. Take precaution in chutes or gullies with larger starting zones, crossloaded features, or terrain that lends no escape route.

advisory discussion

Yesterday’s skier triggered avalanche in the Bardini chutes is a good reminder that freshly fallen snow needs time to adjust and settle, especially in steeper and complex terrain.

Weather and CURRENT CONDITIONS
weather summary

Looks like the brunt of our latest storm is on the wane, but continued light snowfall and winds will continue through today with partly cloudy to mostly cloudy skies for the forecast area. SW winds will blow in the 15-25mph range for the mid elevations and 25-40mph up high with ridge top gusts in the 60’s. Temperatures will be above freezing (29-37F) in the lower elevations while high elevations will stay in the 20’s today. 3” of snow is slated to fall today with continued light accumulations through tonight (1-6”). Overcast skies and continued chance of light snows will continue through Friday with colder temperatures.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Thursday Thursday Night Friday
Weather: Partly cloudy then becoming mostly cloudy. Chance of snow showers through the day. Snow levels below 7000 feet. Chance of precipitation is 30%. Cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 55%. Mostly cloudy. Chance of snow showers through the day. Snow levels below 7000 feet. Chance of precipitation is 25%.
Temperatures: 29 to 37. deg. F. 14 to 20. deg. F. 20 to 30. deg. F.
Mid Slope Winds: Southwest 15 to 25 mph with gusts to 45 mph. Southwest 15 to 25 mph with gusts to 40 mph. Southwest 15 to 25 mph with gusts to 35 mph.
Expected snowfall: 80% probability of up to 3 inches. 20% probability of 3 to 6 inches. | SWE = less than 0.10 inch. in. 80% probability of 1 to 4 inches. 20% probability of 4 to 6 inches. | SWE = up to 0.20 inch. in. 30% probability up to 1 inch. 70% probability of no accumulation. | SWE = less than 0.10 inch. in.
Over 10,000 ft.
Thursday Thursday Night Friday
Weather: Partly cloudy then becoming mostly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 40%. Cloudy. Snow showers likely. Snow levels below 7000 feet. Chance of precipitation is 65%. Mostly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 35%.
Temperatures: 21 to 27. deg. F. 7 to 12. deg. F. 12 to 18. deg. F.
Ridge Top Winds: Southwest 25 to 40 mph with gusts to 60 mph decreasing to 20 to 30 mph with gusts to 45 mph in the afternoon. Southwest 20 to 35 mph with gusts to 45 mph. Southwest 15 to 30 mph with gusts to 40 mph.
Expected snowfall: 90% probability of up to 3 inches. 10% probability of 3 to 6 inches. | SWE = less than 0.10 inch. in. 70% probability of 3 to 6 inches. 30% probability 6 to 9 inches. | SWE = 0.15-0.25 inch. in. 30% probability up to 1 inch. 70% probability of no accumulation. | SWE = less than 0.10 inch. 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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