Avalanche Advisory: Thursday - Feb 14, 2019

THIS AVALANCHE ADVISORY EXPIRED ON February 15, 2019 @ 6:47 am
Avalanche Advisory published on February 14, 2019 @ 6:47 am
Issued by Steve Mace - ESAC

HIGH Avalanche Danger exists at all elevations today.   Continued heavy precipitation coupled with strong to extreme southwest winds has created hazardous conditions. Large natural and human triggered Avalanches are very likely. Travel in, near or underneath avalanche terrain is not recommended.

 

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.

4. High

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Below Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
    Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
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Over the last couple of days we have see strong to extreme winds even at lower elevations.  Wind speeds are expected to rise today accompanied by heavy snowfall. Large fresh wind slab development will be likely in areas where terrain features encourage drifting such as the leeward sides of ridgelines and the sidewalls of gullies.  Use surface clues such as blowing snow, new cornice growth, and uneven snow surface to identify and avoid wind-loaded areas.  It is essential to keep in mind that extreme winds will continue to distribute snow in unpredictable ways.  It will be possible to find areas of wind deposit in places you may not normally expect such as further down slopes and in more protected areas even at lower elevations.

Avalanche Problem 2: Storm Slab
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As temperatures drop sharply this morning expect low elevation rain to turn to heavy snowfall. Over 2’ of new snow and 2” of snow water equivalent is expected throughout the day today.   Storm slab avalanches will be likely particularly in areas protected from the wind.  Watch for signs of instability such as shooting cracks, wumphing or recent avalanche activity.  Travel on or underneath slopes greater than 30° is not recommended.

 

Avalanche Problem 3: Loose Wet
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Loose wet avalanches will be possible this morning as rain continues at lower elevations.  Expect The likelihood to decrease drastically as the freezing level drops and the rain changes to snow. 

advisory discussion

The weather over the last couple of days has been a mixed bag bringing rain above 9000’ at times and extreme winds from the southwest. Structure in the upper levels of the snowpack is likely to be varied across different aspects and elevations making for complicated problems today.  Dense, saturated snow will be overlying unconsolidated storm snow in protected areas at lower elevations while thick sensitive wind board may be overlying that same storm snow in exposed areas at mid and upper elevations.  Significant snowfall today will only further stress this structure.  Extreme caution is recommended, and travel in or adjacent to avalanche terrain should be avoided. 

Weather and CURRENT CONDITIONS
weather summary

*Winter Storm Warning in Effect until Thursday, 02-14 at 10 PM*

 

Stormy conditions are expected today with lower elevation rain changing to heavy snowfall as freezing levels drop sharply this morning.  Highs in the low 30's are expected today with 15-23” of snow and gusts up to 120 MPH expected at upper elevations.   Winds will decrease slightly after midnight tonight as heavy snow continues. Up to 13” of snow is expected this evening as temperatures drop into the mid-teens.

Heavy snow, strong winds, and cold temperatures will remain tomorrow as the Atmospheric River continues to flow through the area.

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: Cloudy. Rain in the morning. Snow through the day. Snow levels 8000 feet decreasing to 7000 feet in the afternoon. Chance of precipitation is 100%. Mostly cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 80%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 33 to 41. deg. F. 18 to 23. deg. F. 20 to 28. deg. F.
Mid Slope Winds: South 30 to 40 mph shifting to the southwest 30 to 50 mph in the afternoon. Gusts up to 75 mph. Southwest 30 to 50 mph with gusts to 80 mph. Southwest 20 to 35 mph with gusts to 45 mph.
Expected snowfall: 70% probability of 10 to 18 inches. 30% probability of 16 to 22 inches. | SWE = 1.10-1.60 inches. in. 80% probability of 6 to 12 inches. 20% probability of 8 to 15 inches. | SWE = 0.40-0.65 inch. in. 90% probability of 7 to 13 inches. 10% probability of 15 to 20 inches. | SWE = 0.40-0.65 inch. in.
Over 10,000 ft.
Thursday Thursday Night Friday
Weather: Cloudy. Snow. Snow levels 8500 feet decreasing to 7000 feet in the afternoon. Chance of precipitation is 100%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 95%.
Temperatures: 26 to 32. deg. F. 12 to 17. deg. F. 13 to 18. deg. F.
Ridge Top Winds: Southwest 50 to 70 mph increasing to 70 to 80 mph in the afternoon. Gusts up to 120 mph. Southwest 65 to 85 mph decreasing to 45 to 65 mph after midnight. Gusts up to 115 mph. Southwest 35 to 55 mph with gusts to 80 mph.
Expected snowfall: 80% probability of 15 to 23 inches. 20% probability of 25 to 35 inches. | SWE = 1.20-2.10 inches. in. 80% probability of 7 to 13 inches. 20% probability of 10 to 15 inches. | SWE = 0.55-0.80 inch. in. 90% probability of 9 to 15 inches. 10% probability of 15 to 20 inches. | SWE = 0.55-0.80 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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