Avalanche Advisory: Friday - Feb 1, 2019

THIS AVALANCHE ADVISORY EXPIRED ON February 2, 2019 @ 6:47 am
Avalanche Advisory published on February 1, 2019 @ 6:47 am
Issued by Chris Engelhardt - Eastern Sierra Avalanche Center

The avalanche danger is LOW at all elevations today and will increase to MODERATE for WIND & STORM SLAB Friday evening/night for the mid to upper elevations. Be prepared for changing conditions and fresh sensitive slab development with the onset of the next significant winter storm.

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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Mostly cloudy conditions and mild temperatures will linger today before the next winter storm moves into the area this evening. Heavy snow is expected at times overnight and this combined with moderate to strong SW winds will start building fresh wind slab on leeward NORTHERLY aspects. New snow will be falling on a variety of old snow surfaces from firm smooth windboard, loose dry areas and potentially some Surface Hoar that was observed in the Bishop Creek drainage on 1/30. If out super early tomorrow, be observant for signs of instability such as shooting cracks, whumpfing of the snowpack, and fat or loaded looking areas of snow.

Avalanche Problem 2: Storm Slab
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If snowfall totals add up on the high end Friday night, fresh storm slab will be blanketing the mountains and will be initially sensitive and reactive to skier triggers before it's given time to settle and bond. Upper and Mid elevations could see the most snow totals overnight. Although relative warm temperatures will help new snow bond to old snow surfaces, travelers must always evaluate terrain carefully after fresh snowfall and adjust plans accordingly.

 

advisory discussion

The main take away point for folks who are looking to get out on an early dawn patrol Saturday morning is the unknown of how much snow will fall Friday evening and night. Good homework on what transpired overnight will help one adjust and formulate good travel plans. Avalanche Danger will likely be elevated to MODERATE by Saturday morning but could be higher if the storm decides to strike early with big accumulations and winds overnight. A great resource to check local weather conditions and snow totals (particularly for the Mammoth area) is the Mammoth Mountain Ski Patrol website

Weather and CURRENT CONDITIONS
weather summary

Mild temperatures and mostly cloudy conditions are on tap for today before the oncoming set of storms slated to hit the Sierra Friday night through Saturday and then again Sunday-Monday. Moderate to strong south winds are projected for Friday with a slight chance of precipitation during the day. Mild temperatures will continue today (37-43F lower/mid and 30-36F upper elevations).

The National Weather Service has initiated a WINTER STORM WARNING going into effect at 4pm this evening. The main event for the storm is supposed to hit during the day Saturday, but Friday night could see anywhere from 2-10” in the forecast area. If snow totals fall on the high end and combine with strong S-SW winds; this will result in decent accumulations and increasing avalanche hazard early Saturday morning. Upwards of 2 feet of snow are projected for Saturday in the upper elevations with periods of whiteout conditions. It should be an exciting weekend for all.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 5%. Cloudy. Snow likely. Snow levels below 7000 feet. Chance of precipitation is 70%. Heavy snow. Snow levels below 7000 feet. Chance of precipitation is 100%.
Temperatures: 37 to 43. deg. F. 25 to 30. deg. F. 29 to 35. deg. F.
Mid Slope Winds: South 15 to 25 mph. Gusts up to 40 mph in the afternoon. South 15 to 30 mph with gusts to 45 mph. Southeast 15 to 25 mph. Gusts up to 45 mph.
Expected snowfall: No accumulation. | SWE = none. in. 80% probability of 2 to 6 inches. 20% probability of 6 to 10 inches. | SWE = 0.15-0.40 inch. in. 80% probability of 14 to 22 inches. 20% probability of 22 to 28 inches. | SWE = 1.00-1.50 inches. in.
Over 10,000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Snow levels 7000 feet. Chance of precipitation is 5%. Cloudy. Chance of snow in the evening, then snow after midnight. Snow levels below 7000 feet. Chance of precipitation is 85%. Heavy snow. Snow levels below 7000 feet. Chance of precipitation is 100%.
Temperatures: 30 to 36. deg. F. 20 to 25. deg. F. 22 to 28. deg. F.
Ridge Top Winds: Southwest 15 to 25 mph with gusts to 45 mph increasing to south 25 to 35 mph with gusts to 60 mph in the afternoon. South 30 to 50 mph with gusts to 80 mph. South 35 to 55 mph with gusts to 80 mph decreasing to 25 to 40 mph with gusts to 60 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. in. 80% probability of 3 to 7 inches. 20% probability of 7 to 10 inches. | SWE = 0.30-0.55 inch. in. 80% probability of 19 to 27 inches. 20% probability of 27 to 32 inches. | SWE = 1.15-1.90 inches. 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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