THIS AVALANCHE ADVISORY EXPIRED ON March 21, 2020 @ 7:05 am
Avalanche Advisory published on March 20, 2020 @ 7:05 am
Issued by Dave Bingaman - Payette Avalanche Center
bottom line

The Avalanche Hazard is Moderate today in upper elevation wind affected terrain. Human triggered wind slabs are possible near ridge tops and will be most likely on Northerly slopes.  Pay attention in gullies and other terrain features that caught wind blown snow over the last few days as winds changed directions  The potential for wet, loose avalanches of various sizes will rise with the temperatures on sun affected terrain throughout the day.

How to read the advisory


  • 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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Wind slabs have been a problem for the last few weeks.  Last weekend's storm and the last few days have been fairly windy in the upper elevations.  Conditions prior to the last storm provided a variety of bed surfaces and buried layers for wind slabs to fail on. As the weather warms, the wind slab problem will diminish but remember if you are skiing shady, northerly terrain you increase your risk of finding scattered wind slabs.  Even small avalanches can have big consequences if you are in committing terrain. 

Avalanche Problem 2: Loose Wet
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As the temperature climbs today and the sun begins to affect slopes today, you can expect natural or human triggered wet, loose avalanche conditions to increase.  Most of these will be occurring in very steep terrain at or near areas with exposed rocks.  If you are searching for steep corn filled gullies today, you will be in prime terrain for wet, loose slides.  Generally speaking, wet loose avalanches are pretty slow moving, but can easily carry you into areas or obstacles where you don't want to go.  

Fortunately, this problem is fairly easy to manage by keeping close track of the snow conditions. 

  • Is the sun directly hitting the slope you’re on or below? 
  • Is the snow getting soft and mushy?
  • Can the snow no longer support your weight if you step off your skis or sled?

If you find yourself in this situation, it is time to move to cooler, shaded slopes.

advisory discussion

If you are coming to visit the McCall, Donnelly or Cascade areas over the next few days, please be aware that we are a small, rural area with limited EMS, Medical and other resources available.  Many bars and restaurants are closed or open only for take out orders.  We are taking the Corona Virus threat very seriously and if you are a visitor, we need you to take the precautions described by the CDC to help keep our communities safe.  You can find more info about open businesses and other community information at: https://valley-county-covid-19-response-valleycounty.hub.arcgis.com/

recent observations

After last weekend's spring storm, several areas experienced a small, natural avalanche cycle primarily in wind loaded terrain on the Northern half of the compass.  These slabs are going to linger in this terrain but are by no means widespread.   There is still plenty of soft snow to be had on shady northern slopes which is where you are most likely to find wind slabs.  If you are searching for soft snow in all the right places, look for pillows, sculpted or textured snow.  If you are skiing or riding and notice a change in the consistency of the snow you are traveling though especially if it feels stiffer or hollow, you are most likely getting into wind affected snow or even on a wind slab.  If you are searching for corn, sleep in and wait for conditions to warm up.  Pay attention to the conditions as they change and practice good travel protocol.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 27 deg. F.
Max. temperature in the last 24 hours: 36 deg. F.
Average wind direction during the last 24 hours: Variable, S then ENE
Average wind speed during the last 24 hours: 4 mph
Maximum wind gust in the last 24 hours: 19 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

.SHORT TERM...Today through Sunday night...Moisture and
instability near the northern fringes of an upper low in Nevada
will lead to isolated afternoon showers over the higher
terrain. A drier and more stable northwest flow aloft will move
in this weekend for a slight chance of showers along the ID/NV
border and dry conditions across all areas on Sunday. Winds will
be light and variable through the period. Temperatures will trend
slightly warmer each day, with highs in the 60s across the lower
valleys.

.LONG TERM...Monday through Friday...A significant trough will
dig along the Pacific Northwest coast on Monday, and eventually
absorb the closed Low stalled off the California coast. This will
create dynamic and moist southwest flow over OR/ID that will
generate prime conditions for showers and isolated thunderstorms
Mon through Wed. The colder air aloft will aid in greater
instability during the afternoon/early evening periods. In
addition, snow levels will gradually lower each day, resulting in
several days of light snow accumulations for the mountain
elevations. Above normal temperatures on Monday will quickly
surrender to slightly cooler than normal temperatures for Tue and
Wed. Thereafter, brief drier weather will return for Thursday
ahead of the next active trough to arrive Fri/Sat.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Mostly sunny, with a high near 46. Calm wind. Partly cloudy, with a low around 17. Calm wind. Sunny, with a high near 45. Calm wind.
Temperatures: 46 deg. F. 17 deg. F. 45 deg. F.
Wind direction: Calm Calm Calm
Wind speed: 0 0 0
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Isolated snow showers after noon. Mostly sunny, with a high near 37. Calm wind becoming northwest around 5 mph in the afternoon. Chance of precipitation is 20%. Partly cloudy, with a low around 22. Northeast wind 5 to 7 mph. Sunny, with a high near 35. North northeast wind around 5 mph becoming calm.
Temperatures: 37 deg. F. 22 deg. F. 35 deg. F.
Wind direction: NW NE NNE
Wind speed: 5 5-7 5
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Payette National Forest and the Payette Avalanche Center. This advisory covers the West Central Mountains between Hard Butte on the north and Council Mountain on the south. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires at midnight on the posted day unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.