THIS AVALANCHE ADVISORY EXPIRED ON March 3, 2020 @ 7:08 am
Avalanche Advisory published on March 2, 2020 @ 7:08 am
Issued by George Halcom - Payette Avalanche Center
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The Avalanche Hazard today is Low.  Remember though that LOW hazard does not mean NO hazard.  It means that natural avalanches are unlikely today but you may still encounter isolated areas where you could trigger a wind slab in high elevation, wind loaded terrain.  Roller ball and wet, loose activity will be small on Sunny slopes today.  Pay attention to what the Northerly winds have done in areas where there is still soft snow.

How to read the advisory


  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Wind Slab
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  • Likelihood ?
    Certain
    Very Likely
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    Possible
    Unlikely
  • Size ?
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Granite Mountain Weatherstation

Small, wind slabs are still possible in high, alpine areas that were loaded by strong winds yesterday and earlier this week. You may still be able to trigger these 6-12" thick slabs, especially in areas that had either a thin crust or a layer of faceted snow left over from last weeks high pressure conditions. 

These wind slabs will likely not spread out or propagate much further than the area under your skis or snowmobile, but remember if you are in steeper or complex terrain, even a small avalanche can have big consequences. As you travel, look for slopes that don't have the obvious visual clues of wind affect;  ripples across a slope or deeper deposits of snow drifted in under cornices or cliffs should be avoided or managed as potentially problematic areas.   

Northerly winds increased yesterday with gusts in the mid 20's.  There isn't  much snow available for transport but be aware of the effect these winds are having on the snowpack in the northerly terrain.

Cornices are large right now.  Avoid traveling directly above or below large overhanging cornices, they may fail unpredictably or further back than you are expecting.

recent observations

Yesterday we observed some small loose activity from the Sun, but it was far from warm under the North winds that pushed around the little snow that we got overnight, maybe 2-3 inches in the uppermost elevations. The wind created drifts and scoured the soft snow off some ridges leaving a sheen in some places. Stability is much better than the snow quality, but finding good skiing and riding is still possible in areas that are untracked, but conditions are challenging on many slopes. 

 

 

 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 13 deg. F.
Max. temperature in the last 24 hours: 19 deg. F.
Average wind direction during the last 24 hours: ENE
Average wind speed during the last 24 hours: 8 mph
Maximum wind gust in the last 24 hours: 24 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: NA inches
weather

Area Forecast Discussion
National Weather Service Boise ID
308 AM MST Mon Mar 2 2020

.SHORT TERM...Today through Wednesday night...A dry northwest
flow will support breezy conditions this afternoon, though not to
the magnitude of yesterday`s wind. Most of the area will remain
dry through the period as flow aloft becomes more westerly
through Wednesday. A couple of weak shortwave troughs will graze
the northern zones, bringing a chance for light snow to the
e-central Oregon and w-central Idaho mountains on Tuesday and
again Wednesday. Precipitation totals from these systems will be
light with liquid amounts less than a tenth of an inch and
snowfall less than an inch. Temperatures will warm through
period, with highs running 5-10 degrees above normal by Wednesday.

.LONG TERM...Thursday through Monday...An upper level ridge over
the Intermountain Region on Thursday is forecast to move east of
the Rockies Thursday night and Friday, as an upper level trough
from the Gulf of Alaska approaches the northwest coast.
Temperatures will be 10-15 degrees above normal both days, with no
precipitation. The trough will begin moving inland Friday night,
spreading showers into southeast Oregon and the central Idaho
mountains Friday night and the rest of our area on Saturday. Snow
levels 4000-5000 feet on Saturday will lower to the valley floors
by Sunday morning, but the probability of measurable precipitation
will decrease to only a slight chance in the valleys. Scattered
snow showers will continue over the mountains through Monday.
Temperatures will cool to around 5 degrees above normal on
Saturday and near normal Sunday and Monday.

&&

.AVIATION...VFR under mostly clear skies today. Increasing clouds
tonight with a chance of snow showers over the mountains of Baker
County Oregon and west central Idaho late tonight and Tuesday
morning. Surface winds variable less than 10 kts, becoming
northwest 10-15 kts after 18z. Winds aloft at 10k ft MSL north
30-40 kts.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Mostly sunny, with a high near 34. Calm wind. A 20 percent chance of snow after 11pm. Mostly cloudy, with a low around 22. Calm wind. Mostly cloudy, with a high near 39. Calm wind becoming south around 5 mph in the afternoon.
Temperatures: 34 deg. F. 22 deg. F. 39 deg. F.
Wind direction: Calm Calm S
Wind speed: 0 0 5
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Mostly sunny, with a high near 27. West wind 3 to 5 mph. A 40 percent chance of snow, mainly after 11pm. Mostly cloudy, with a low around 21. West wind 5 to 7 mph. New snow accumulation of less than one inch possible. A 30 percent chance of snow before 11am. Mostly cloudy, with a high near 29. West southwest wind 5 to 7 mph. New snow accumulation of less than a half inch possible.
Temperatures: 27 deg. F. 21 deg. F. 29 deg. F.
Wind direction: W W WSW
Wind speed: 3-5 5-7 5-7
Expected snowfall: 0 in. less than one in. less than one half 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.