THIS AVALANCHE ADVISORY EXPIRED ON March 28, 2019 @ 7:08 am
Avalanche Advisory published on March 27, 2019 @ 7:08 am
Issued by George Halcom - Payette Avalanche Center
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The Avalanche Hazard is Considerable Today. Gusty winds will continue to form wind slabs in upper elevation leeward and exposed terrain, and may be sensitive to the weight of a skier or rider. Natural avalanches are possible, especially in wind-loaded, steep terrain. Some of the new snow may not bond well to older Sun and rain crusts and may produce loose dry sluffs.

How to read the advisory


  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Monday we saw some pretty gusty winds that transported snow and created drifts and wind slabs in upper elevation terrain. Some of the surfaces that the newer snow was deposited onto were slick rain crusts, and or Sun crusts, and are taking some time to bond.

Today, we are going to see another round of snow and gusty winds in the 20 MPH range through the evening. Be on the lookout for signs of wind slab formation like etching in the snow surface, drifts, pillows, and hollow sounding snow, or shooting cracks.

 

 

 

 

Avalanche Problem 2: Loose Dry
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Upper elevations have picked up around 6 inches in the last 48 hours that may take some time to bond to the Sun and rain crusts that have formed. Another 2-6 inches of snow through tonight is forecasted, and will increase the likely hood of loose dry avalanches up to a foot deep on steep slopes. 

advisory discussion

PAC will issue 3 Advisories per week through April 5. 

Your Observations are extremely helpful and appreciated by all backcountry users.  If you have not checked our our Observations page, it is really easy to add snow or avalanche info.  Drop down menus and prompts will lead you through it and it is easy to add photos.

Please be aware that there are areas that are CLOSED to motorized traffic in the McCall, Goose Lake and greater West Mountains area.  Just because there are tracks in some areas, does not mean they are open.  Please respect all users and closures.  See the Payette Winter Travel Maps for clarification.  Both the East and West maps can be downloaded on the Avenza app on your phone or are available at trailheads and local shops.   IT IS YOUR RESPONSIBILITY TO KNOW WHERE YOU ARE AND WHERE THESE CLOSURES EXIST. 

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: 27 deg. F.
Average wind direction during the last 24 hours: SE
Average wind speed during the last 24 hours: 6 mph
Maximum wind gust in the last 24 hours: 18 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

 

 

 

Area Forecast Discussion
National Weather Service Boise ID
351 AM MDT Wed Mar 27 2019

.SHORT TERM...Today through Thursday...Upper level low off the
west coast will continue to bring showers and thunderstorms to the
region in the short term. Showers have been concentrated along a
stalled warm frontal boundary this morning across mainly
Southwest Idaho. This front will slowly lift north today with
passage of a weak embedded shortwave. The shortwave could be the
focus for thunderstorm development this afternoon though cloud
cover will likely limit the coverage. Stronger cells could
produce brief heavy rain and gusty winds. SHowers will diminish
from west to east tonight with passage of a weak cold front. The
upper level low remains off shore on Thursday keeping moist
unstable airmass in place. Expect more convective showers and
possible thunderstorms to develop in the afternoon. Temperatures
will remain around normal today falling below normal on Thursday.

.LONG TERM...Thursday night through Tuesday...A broad upper
trough will keep unsettled conditions over the region through
Saturday. Shower development will be diurnal in nature and focus
over the higher terrain. Snow levels will hold around 5k feet
through Friday. A short wave ridge pushes into the Pacific NW late
Saturday and Sunday for a brief period break in the
precipitation. The next system pushes into the area by Monday for
another round of rain and and snow. Temperatures are near normal
through the period.

&&

.AVIATION...Mainly VFR. Widespread showers with isolated
thunderstorms developing after 27/18Z. Local mountain obscuration
and MVFR conditions in mountain valleys through Thursday. Light
surface winds will increase to 10-20 kts after 18Z today. Winds
aloft at 10k ft MSL: southwest 20-35 kts.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Showers likely, then showers and possibly a thunderstorm after noon. High near 44. Calm wind becoming south around 6 mph in the afternoon. Chance of precipitation is 80%. Showers and possibly a thunderstorm before midnight, then a chance of showers. Low around 32. South wind around 5 mph becoming calm in the evening. Chance of precipitation is 80% Rain and snow showers, becoming all rain after noon. Some thunder is also possible. High near 43. Light south wind. Chance of precipitation is 80%. New snow accumulation of less than a half inch possible.
Temperatures: 44 deg. F. 32 deg. F. 43 deg. F.
Wind direction: S S S
Wind speed: 6 5 becoming calm Light
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow showers. Some thunder is also possible. High near 34. South southeast wind 7 to 11 mph, with gusts as high as 23 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 3 inches possible. Snow showers, mainly before midnight. Some thunder is also possible. Low around 25. South wind 6 to 10 mph, with gusts as high as 21 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible. Snow showers. Some thunder is also possible. High near 32. South southwest wind around 7 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches possible.
Temperatures: 34 deg. F. 27 deg. F. 32 deg. F.
Wind direction: SSE S SSW
Wind speed: 7-11, Gusts 23MPH 6-10, Gusts 21 MPH 7 MPH
Expected snowfall: 1-3 in. 1-3 in. 1-3 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.