Avalanche Advisory: Saturday - Feb 16, 2019

THIS AVALANCHE ADVISORY EXPIRED ON February 17, 2019 @ 6:39 am
Avalanche Advisory published on February 16, 2019 @ 6:39 am
Issued by Steve Mace - ESAC

HIGH Avalanche danger will remain at upper elevations today while low and mid elevations will drop to CONSIDERABLE.  Dangerous avalanche conditions exist at all elevations.  Cautious route-finding and conservative decision-making will be essential today. When in doubt it's best to avoid avalanche terrain.

4. High

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

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.
    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. 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 will still be possible to find isolated areas of wind slab at lower elevations.  Gale force winds over the last couple days have redistributed snow in unpredictable ways. Don’t be surprised to find wind loading in areas you may not normally expect such as further down slopes and in more sheltered areas. 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 and very low density. As the snowfall rates start to slow down it is important to give things time to settle. Sensitive storm slab avalanches will still be possible today. Watch for signs of instability such as shooting cracks, wumphing or recent avalanche activity, and be aware that loose unconsolidated sloughs can entrain large amounts of snow and potentially carry a skier through some unpleasant terrain. Use extreme caution if traveling on or underneath slopes greater than 35°.

advisory discussion

With the holiday weekend upon us, it is important to remember that dangerous conditions exist at all elevations. Don’t let the fresh snow lure you into making bad decisions. Wind slabs will be the primary concern today, but it will also be important to do your own localized assessments to evaluate surface instabilities.  Practice safe travel technics and use conservative route choice if heading into the backcountry today. 

 Recent observations have found buried rain crust well over 10000’. While new snow appears to be bonding well to this crust, it can still be found on the surface in more windswept areas and at lower elevations making for difficult travel.  

recent observations
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2/15- Mammoth Area, New snow and rain crust in the Sherwins

2/15- Mammoth Area, Snow Conditions in the Sherwins

2/15- Mammoth Area, storm Instabilities in the Sherwins

2/15- Bishop Area, Snow conditions in Jawbone Canyon.

2/15- Lundy Canyon Snow conditions

2/14- Mammoth Area, Very strong winds in the Sherwins

2/14- Mammoth Area, Forest trail Knoll, Very strong winds

Weather and CURRENT CONDITIONS
weather summary

*Winter Storm Warning in effect until 1200 pm Sunday

Snow showers will continue today with moderate to strong winds and cold temperatures. Expect to see 3-7 inches of new snow and highs in the mid teens at upper elevations.  Winds will continue out of the southwest with ridge top gusts expected to reach 80 mph.  The winds will decrease significantly tonight as the temperature drops to near zero.  2-5” of snow is possible this evening.

 

Tomorrow we can expect a slight break in the storm with snow showers possible in the morning. Temperatures will remain cold, and winds will continue to slow down.  Enjoy the break in the storm because another system seems to be approaching the area for Wednesday. 

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Saturday Saturday Night Sunday
Weather: Mostly cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 85%. Mostly cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 60%. Cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 85%.
Temperatures: 16 to 26. deg. F. 5 to 10. deg. F. 13 to 21. deg. F.
Mid Slope Winds: Southwest 20 to 35 mph with gusts to 50 mph. Southwest 15 to 25 mph. Gusts up to 45 mph decreasing to 30 mph after midnight. West around 15 mph with gusts to 25 mph.
Expected snowfall: 80% probability of 3 to 7 inches. 20% probability of 5 to 10 inches. | SWE = 0.15-0.25 inch. in. 70% probability of 2 to 5 inches. 30% probability of 4 to 8 inches. | SWE = up to 0.15 inch. in. 70% probability of 1 to 4 inches. 30% probability of 3 to 6 inches. | SWE = up to 0.20 inch. in.
Over 10,000 ft.
Saturday Saturday Night Sunday
Weather: Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%. Mostly cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 70%. Cloudy. Snow showers likely in the morning, then snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 9 to 15. deg. F. Zero to 5 above zero. deg. F. 6 to 11. deg. F.
Ridge Top Winds: Southwest 40 to 55 mph decreasing to 30 to 45 mph in the afternoon. Gusts up to 80 mph. West 25 to 35 mph with gusts to 60 mph shifting to the southwest 15 to 30 mph with gusts to 40 mph after midnight. West 15 to 25 mph with gusts to 35 mph.
Expected snowfall: 80% probability of 3 to 7 inches. 20% probability of 6 to 12 inches. | SWE = up to 0.30 inch. in. 70% probability of 2 to 5 inches. 30% probability of 4 to 8 inches. | SWE = up to 0.20 inch. in. 70% probability of 1 to 4 inches. 30% probability of 3 to 6 inches. | SWE = up to 0.20 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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