Avalanche Advisory published on March 6, 2020 @ 7:30 am
Issued by Dave Bingaman - Payette Avalanche Center
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The Avalanche Hazard is LOW today.   As the temperature increases, watch for increasing wet,loose avalanche hazard especially on slopes facing the sun.  You can reduce your exposure to wet, loose avalanches by staying on cooler, shady slopes where you are more likely to find soft snow.  Avoid traveling on or below large, overhanging cornices. Warm temperatures increase the potential for cornice failure.

How to read the advisory

  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Loose Wet
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Upper elevation temperatures overnight did not drop below freezing although winds may have cooled things down enough for a light refreeze.  Valley temperatures today will be over 50 and upper elevation temps should be just above 40 although cloud cover may make it feel slightly cooler.  If you are seeking corn or steep sunny lines, pay attention to how deep you are sinking into the snowpack and how much snow is moving with you or on nearby slopes.  Timing is critical with spring conditions, if the snowpack is getting too soft or is looking like a melting snowcone on a hot summer day, it is time to move to cooler slopes.  

recent observations

We toured north of Hard Butte yesterday and found a mixed, but surprisingly good bag of snowmobile and ski conditions.  WSW winds were consistent through the day with some gusts reaching into the upper 20's.  Despite the lack of fresh snow, there was snow moving and pluming off the ridges.  We saw some recent wind slab crowns near ridges on loaded northerly terrain but they were extremely isolated and the areas that were loaded were pretty easy to identify.  We were able to search out some great conditions with shallow soft snow on steep and stable north facing slopes.  South facing slopes warmed into near perfect corn conditions up high and got a little sloppy down low.   Roller balls and wet, loose activity was increasing but confined mostly to sunny, wind protected lower elevation slopes.  Afternoon snowmobiling on the sunny slopes was really good and provided consistent, smooth edging and climbing on our ride back out.   

Overall, we have very stable conditions as a result of the last 2 weeks of high pressure, but that is about to change.  Crusts and faceted snow have had a chance to grow and will create some shallow storm and wind slab potential through the weekend if wind forecasts and snow totals are accurate.  Any new snow will likely have a hard time bonding to the old snow surfaces for a few days.  Even during high pressure, green light conditions, it is important to travel safely and minimize your exposure in steep terrain.  Good travel protocols including one at a time on steep slopes is an easy way to keep your group safe.  Pay attention to changing conditions over the next few days and adapt your travel accordingly.


CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 34 deg. F.
Max. temperature in the last 24 hours: 40 deg. F.
Average wind direction during the last 24 hours: WNW
Average wind speed during the last 24 hours: 8 mph
Maximum wind gust in the last 24 hours: 23 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: NA inches

.SHORT TERM...Today through Sunday night...A relatively mild start
this morning will lead to another warm day with high temperatures
in record territory again this afternoon. Today will feature more
high-based cloud cover as moisture aloft and strengthening
southwest flow interacts with higher terrain. Steady south to east
surface winds will become gusty this afternoon, especially across
higher terrain of southeast Oregon where gusts 25 to 35 MPH will
be common. The winds and mild temperatures are in advance of an
upper level trough and accompanying cold front which will move
into the interior NW on Saturday. Light precipitation will develop
ahead of the system in the w-central Idaho mountains Friday
night, but the bulk of the rain/snow will come with the frontal
passage on Saturday. While flow aloft will focus heavier
precipitation in the mountains, forcing along the cold front will
support shower development across lower terrain and bring
potential for gusty winds of 30-40 MPH. Snow levels will drop to
4500-5500 feet by Saturday afternoon, but with temperatures above
freezing, little accumulation is expected below 5500 feet on
Saturday. Preciptiation scatters out Saturday evening, with only
the w-central ID mountains keeping a chance of showers into Sunday
morning. Most areas are dry on Sunday under a weak southwest flow
aloft as the main low remains positioned off the West Coast.
Clouds and the chance of showers increases Sunday night as a
seperate shortwave trough enters the Pacific NW. Temperatures will
cool 10 to 15 degrees from Friday to Saturday, and another 4 to 8
degrees from Saturday to Sunday, putting them near normal.

.LONG TERM...Monday through Friday...Light scattered showers will
linger through Monday as an upper level trough passes through the
region. Snow levels will stay near 3000-4000 ft MSL before
temperatures rebound to 5-7 degrees above normal. Conditions will
remain mostly dry and mild through the week, with possible snow
showers grazing the West Central Idaho Mountains on Tuesday. The
next system is expected to move across the West Coast on Friday,
though there is lots of spread over the track of the low pressure
center. As of now, the system is anticipated to track southward
over the Great Basin and spread rain and snow across the West
Central Mountains on Thursday and become more widespread across SE
OR/SW ID on Friday.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Partly sunny, with a high near 50. Calm wind becoming south 5 to 9 mph in the afternoon. A 20 percent chance of showers after 11pm. Mostly cloudy, with a low around 37. Light south southeast wind becoming south 6 to 11 mph after midnight. Rain and snow showers. High near 41. South southwest wind 7 to 10 mph, with gusts as high as 26 mph. Chance of precipitation is 100%. New snow accumulation of less than a half inch possible.
Temperatures: 50 deg. F. 37 deg. F. 41 deg. F.
Wind direction: S SSE SW
Wind speed: 5-9 6-11 7-10, Gusts to 26
Expected snowfall: 0 in. 0 in. Trace in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Mostly sunny, with a high near 39. Breezy, with a south wind 18 to 23 mph decreasing to 11 to 16 mph in the morning. A 30 percent chance of snow showers, mainly after 11pm. Mostly cloudy, with a steady temperature around 35. South wind 13 to 17 mph. New snow accumulation of less than a half inch possible. Snow showers. Temperature falling to around 23 by 5pm. South wind 13 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible.
Temperatures: 39 deg. F. 35 deg. F. 30 deg. F.
Wind direction: S S S
Wind speed: 18-26 then 11-16 13-17 13-16, Gusts to 26
Expected snowfall: 0 in. Trace in. 3-5 in.

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.