Avalanche Advisory: Monday - Feb 25, 2019

THIS AVALANCHE ADVISORY EXPIRED ON February 26, 2019 @ 6:19 am
Avalanche Advisory published on February 25, 2019 @ 6:19 am
Issued by Steve Mace - ESAC

The avalanche danger will be MODERATE at mid and upper elevations today while remaining LOW at lower elevations. This is due to the possibility of sensitive wind slabs on specific terrain features.  Expect the danger to rise this afternoon and into the evening as the next winter storm enters the area. It is feasible that the danger level could be in the realm of CONSIDERABLE by the early morning tomorrow. This change will be more pronounced in the areas north of Mammoth, which can expect higher snowfall totals.

2. Moderate

?

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

2. Moderate

?

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

1. Low

?

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
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

As winds increase today and shift to the southwest, expect to find new slab development on leeward slopes where terrain features encourage drifting.  Use surface clues such as blowing snow, drifting, and recent cornice growth to identify and avoid wind-loaded areas.  While northeasterly aspects at upper and mid elevations will be most concerning today, with powerful winds expected it might be possible to find wind slabs developing on isolated terrain features at lower elevations. Expect the size, sensitivity, and distribution of wind slabs to rise quickly as the snow begins to fall this evening. 

advisory discussion

Change is a constant in the mountains and today is no exception.  Wind slabs remain our primary concern today. However, with increasing snow tonight we can also expect storm slab development by the early morning hours tomorrow.  If you find yourself out late tonight or planning an early departure tomorrow expect to find the stability rapidity decreasing.  This approaching storm has been a tricky one to predict.  Snowfall totals will vary significantly across the range with the northern reaches of the forecast zone predicted to receive much more snow than areas further south.   It will be essential to keep an eye on the weather today and keep options open in case things change faster than expected.

recent observations
Submit Snowpack Observations
Submit Avalanche Observations

2/24- Convict Creek, Wind transport in the Old Mans bowl

2/24- Bishop Creek, Basin Mountains Snow conditions

2/23- Lee Vining, Snow Conditions in V Bowl

2/22- Bishop Area, Sensitive wind slabs on Mt Tom

2/22- June Lake, Snow conditions in the Negatives

2/22- June Lake, Reversed Peak Snow conditions

2/22- Mammoth Area, Snow Conditions on Red Cone

Weather and CURRENT CONDITIONS
weather summary

Expect to see a change in the weather today as the next winter storm enters the area.  Skies will be mostly cloudy today with snow showers developing in the afternoon/evening hours. Winds will increase today with gusts expected to reach 80 mph on ridge tops.  Temperatures will reach into the mid 20s at upper elevations.  The bulk of our precipitation will come tonight. Less than 2” is expected during daylight hours today.  Expect the snow to intensify this evening as the southwestern winds increase.  5-8” of snow is possible this evening with gusts expected to reach into the triple digits at upper elevations.

 

Winter weather will continue through the week with the most intense periods of snowfall predicted for Tuesday night.  The northern reaches of the forecast area are expected to see much more snow than the south. 

 

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Monday Monday Night Tuesday
Weather: Partly cloudy. Chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 45%. Mostly cloudy. Snow likely in the evening, then snow after midnight. Snow levels below 7000 feet. Chance of precipitation is 85%. Mostly cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 85%.
Temperatures: 27 to 37. deg. F. 25 to 30. deg. F. 31 to 40. deg. F.
Mid Slope Winds: Southwest 15 to 30 mph increasing to 30 to 45 mph in the afternoon. Gusts up to 60 mph. Southwest 30 to 45 mph with gusts to 70 mph. Southwest 30 to 40 mph with gusts to 70 mph.
Expected snowfall: 90% probability up to 2 inches. 10% probability of 2 to 4 inches. | SWE = less than 0.10 inch. in. 80% probability of 4 to 7 inches. 20% probability of 7 to 10 inches. | SWE = 0.35-0.55 inch. in. 70% probability of 4 to 8 inches. 30% probability of 8 to 12 inches. | SWE = 0.30-0.55 inch. in.
Over 10,000 ft.
Monday Monday Night Tuesday
Weather: Partly cloudy then becoming mostly cloudy. Chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 45%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%. Mostly cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 17 to 27. deg. F. 20 to 25. deg. F. 24 to 31. deg. F.
Ridge Top Winds: Southwest 45 to 65 mph with gusts to 80 mph. Southwest 55 to 75 mph with gusts to 105 mph. Southwest 45 to 65 mph with gusts to 105 mph.
Expected snowfall: 90% probability up to 2 inches. 10% probability of 2 to 4 inches. | SWE = less than 0.10 inch. in. 80% probability of 5 to 8 inches. 20% probability of 8 to 12 inches. | SWE = 0.40-0.65 inch. in. 60% probability of 5 to 8 inches. 40% probability of 8 to 12 inches. | SWE = 0.40-0.65 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.

ESAC receives significant financial support from ...