Avalanche Advisory: Tuesday - Feb 19, 2019

THIS AVALANCHE ADVISORY EXPIRED ON February 20, 2019 @ 6:20 am
Avalanche Advisory published on February 19, 2019 @ 6:20 am
Issued by Chris Engelhardt - Eastern Sierra Avalanche Center

The avalanche danger is MODERATE at Upper elevations today. LOW avalanche danger resides at mid to lower elevations. WIND SLAB and CORNICES are of most concern today. Human triggered avalanches are still possible; identify features of concern and adjust travel plans accordingly.

2. Moderate

?

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

1. Low

?

Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

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

NORTHERLY WINDS persisted yesterday, last night, and will continue to blow at moderate to strong speeds today. There is plenty of transportable snow on northern aspects that will be redistributed to form fresh wind slab on SOUTHERLY and WESTERLY aspects. Although stabilizing, wind slabs on northerly and easterly aspects at higher elevations deserve recognition and evaluation as previous winds were prevailing from the S-W.  With forecasted SUNNY skies today, be aware that solar gain can contribute to loosening of fresh wind deposits on sunny aspects such as E-S-W today. Take note that a RAIN CRUST was created up to around 10000ft during Feb 14/15. This rain crust may create a good sliding surface for freshly deposited wind slab on aspects that were previously wind scoured down to this crust (again…think south and west aspects). Although new snow has been shown to be bonding fairly well to this rain layer where it was buried, pay attention to where it may now just be getting covered up by new cold wind deposits with less bonding potential.

Avalanche Problem 2: Cornice
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

CORNICES have become established on EASTERLY and NORTHERLY aspects throughout the range. Give these curling wavelike features a wide berth and make sure you are well on terra firma on the windward side of ridges where cornices reside. Cornice fall not only is hazardous if it gives way beneath you, but can affect travelers if it falls from above when you are travelling on slopes below. Cornice fall can be the big trigger that start avalanches on slopes below as the falling blocks can be of tremendous weight and scale. Cold temps help to keep these locked up, but with forecasted SUNNY SKIES today be cognizant that solar gain can contribute to loosening freshly formed cornices and other teetering wind deposited formations in alpine terrain--particularly easterly aspects. Cornices are one of the main contributors of fatalities for seasoned guides, skiers, and mountaineers in the alpine environment. Always give cornices extra space, as they can release further back on ridges than expected due to the connectivity of the snow.

advisory discussion

THANKS TO ALL OUR VOLUNTEER OBSERVERS. Enjoy and be safe out there!!!

Weather and CURRENT CONDITIONS
weather summary

Cold temperatures will reside, although it will be a bit warmer than the past few chilly days. Sunny skies are on tap for today! Be prepared for temps in the 20sF (22-28F) below 10000ft and teens to low 20sF (16-21F) above 10000 today. Moderate to Strong Northerly winds will continue today and will switch slightly to the West tonight. A slider system is still looking good for our area beginning Wednesday with light snow accumulations, and another storm is possible for the upcoming weekend.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Tuesday Tuesday Night Wednesday
Weather: Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy then becoming mostly cloudy. Snow showers likely in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 60%.
Temperatures: 22 to 28. deg. F. 6 to 11. deg. F. 17 to 23. deg. F.
Mid Slope Winds: North around 15 mph with gusts to 35 mph. West around 15 mph with gusts to 40 mph. Southwest around 15 mph. Gusts up to 45 mph decreasing to 35 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. in. No accumulation. | SWE = none. in. 50% probability up to 1 inch. 50% probability 1 to 4 inches. | SWE = less than 0.10 inch. in.
Over 10,000 ft.
Tuesday Tuesday Night Wednesday
Weather: Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Mostly cloudy. Snow showers likely in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 70%.
Temperatures: 16 to 21. deg. F. 1 to 6. deg. F. 9 to 14. deg. F.
Ridge Top Winds: North 20 to 30 mph with gusts to 50 mph. Northwest 15 to 30 mph with gusts to 45 mph. Southwest 20 to 35 mph. Gusts up to 55 mph decreasing to 45 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. in. No accumulation. | SWE = none. in. 60% probability up to 1 inch. 40% probability 1 to 4 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.

ESAC receives support from ...