Avalanche Advisory: Wednesday - Mar 6, 2019

THIS AVALANCHE ADVISORY EXPIRED ON March 7, 2019 @ 6:32 am
Avalanche Advisory published on March 6, 2019 @ 6:32 am
Issued by Steve Mace - ESAC

The avalanche danger will rise to HIGH today at mid and upper elevations and CONSIDERABLE at lower elevations.  Dangerous avalanche conditions exist at all elevations today. Cautious route-finding and conservative decision-making will be essential today.  When in doubt it's best to avoid being in or underneath avalanche terrain.

4. High

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Above Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

4. High

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Near Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
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Moderate to strong winds will continue out of the southwest today accompanied by periods of heavy snowfall. Expect to find large sensitive wind slabs on northerly terrain in areas where the topography encourages drifting such as the leeward sides of ridgelines and the sidewalls of gullies.   While fresh wind slab development will be more pronounced at mid and upper elevations, it may be possible to find isolated areas of wind slab at lower elevations. Use surface clues such as blowing snow, drifting, new cornice growth, and uneven snow surface to identify and avoid wind-loaded areas over 35°.  

Avalanche Problem 2: Storm Slab
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Recent observations have found the new storm snow to be largely right-side up, however with another 4-12” of new snow expected today sensitive storm slab avalanches will be likely in areas protected from the wind. Watch for signs of instability such as shooting cracks, wumphing or recent avalanche activity, and be aware that loose unconsolidated sloughs can entrain quite a bit of snow and potentially carry a skier through some unpleasant terrain.  Heightened awareness is recommended in sheltered areas over 35°.

Avalanche Problem 3: Loose Wet
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Loose wet avalanches will be possible today at lower elevations.  Numerous observations yesterday reported warm wet snow, rollerballs, and loose wet point releases. With temperatures expected to be in the mid to upper 30’s today at lower elevations this trend is likely to continue. Be on the lookout for signs of warming particularly if you are traveling near the freezing line, which is expected to hover around 7000’. 

advisory discussion

Large sensitive wind slabs will be the primary concern today however; there are a variety of avalanche problems affecting all elevations today with very different implications for travel.  Careful snowpack evaluation and conservative terrain choices will be essential if you decide to head into the backcountry today. Don’t let the fresh snow lure you into making bad decisions today. Human triggered avalanches are likely today at all elevations, and resulting avalanches have the potential to be large and destructive. It is important to give yourself large margins and remember to consider the terrain above you. When in doubt avoid being in, adjacent to or underneath avalanche terrain.

Weather and CURRENT CONDITIONS
weather summary

 Expect cloudy skies and snow showers to continue through today with a slight chance of thunderstorms in the afternoon.  7-12” of snow is possible today with temperatures expected to be in the mid 20’s at upper elevations. Moderate to strong winds will continue from the southwest today with ridge top gusts expected to reach 80 mph.

Snow showers will continue tonight with 1-4” possible and temperatures expected to drop into the teens. Thunderstorms remain a possibility tonight as well. Expect the wind speeds to decrease slightly after midnight though ridge top speeds will still be strong.

Winter weather will continue for the next few days with cooling temperatures predicted as we move into the weekend.  

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Wednesday Wednesday Night Thursday
Weather: Cloudy. Snow showers through the day. Slight chance of thunderstorms in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 95%. Mostly cloudy then becoming partly cloudy. Snow showers and slight chance of thunderstorms in the evening, then chance of snow showers after midnight. Snow levels below 7000 feet. Chance of precipitation is 70%. Mostly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 45%.
Temperatures: 30 to 38. deg. F. 22 to 27. deg. F. 30 to 38. deg. F.
Mid Slope Winds: South 15 to 30 mph with gusts to 75 mph. South 25 to 35 mph with gusts to 90 mph becoming southwest 15 to 20 mph with gusts to 65 mph after midnight. South 15 to 25 mph with gusts to 45 mph.
Expected snowfall: 80% probability of 5 to 10 inches. 20% probability of 10 to 16 inches. | SWE = up to 0.70 inch. in. 70% probability of 1 to 4 inches. 30% probability of 4 to 8 inches. | SWE = up to 0.25 inch. in. up to 2 inches. | SWE = less than 0.10 inch. in.
Over 10,000 ft.
Wednesday Wednesday Night Thursday
Weather: Cloudy. Snow showers through the day. Slight chance of thunderstorms in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 100%. Mostly cloudy. Snow showers and slight chance of thunderstorms in the evening, then snow showers likely after midnight. Snow levels 7000 feet decreasing to below 7000 feet after midnight. Chance of precipitation is 85%. Mostly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 55%.
Temperatures: 22 to 28. deg. F. 16 to 21. deg. F. 22 to 28. deg. F.
Ridge Top Winds: Southwest 35 to 55 mph with gusts to 80 mph. Southwest 40 to 55 mph decreasing to 30 to 50 mph after midnight. Gusts up to 85 mph. Southwest 25 to 40 mph with gusts to 60 mph shifting to the south 20 to 30 mph with gusts to 45 mph in the afternoon.
Expected snowfall: 80% probability of 7 to 12 inches. 20% probability of 12 to 20 inches. | SWE = 0.60-0.85 inch. in. 70% probability of 1 to 4 inches. 30% probability of 4 to 8 inches. | SWE = up to 0.30 inch. in. up to 2 inches. | 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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