Avalanche Advisory published on March 29, 2019 @ 7:09 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Hazard is Moderate Today. Gusty winds and around a foot of new snow have formed wind slabs in upper elevation leeward and exposed terrain, and may be sensitive to the weight of a skier or rider. Use caution in or around 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 on slopes steeper than 30 degrees.

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
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Monday and Tuesday the West Central Mountains got hammered by some pretty gusty winds around 30 MPH 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 going to take some time to bond. 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
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Upper elevations have picked up around 12 inches in the last 72 hours that may take some time to bond to the Sun and rain crusts that have formed. Loose dry avalanches up to a foot deep are possible on steep slopes. 

Granite MTN Weather Station 7700 FT

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: 21 deg. F.
Max. temperature in the last 24 hours: 29 deg. F.
Average wind direction during the last 24 hours: E
Average wind speed during the last 24 hours: 3 mph
Maximum wind gust in the last 24 hours: 13 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches


Area Forecast Discussion
National Weather Service Boise ID
316 AM MDT Fri Mar 29 2019

.SHORT TERM...Today through Sunday...A slow-moving upper low will
continue across the region today. There will be enough breaks in
the clouds for patchy fog this morning in the northern valleys,
including McCall. Showers associated with the low will be
isolated this morning, but the coverage will increase during the
afternoon. There will be some support for isolated afternoon
thunderstorms as well. The convection will be generally limited to
the higher elevations with little or no activity expected in the
Treasure/Western Magic Valleys. Snow levels will remain around
5000 feet with light snow accumulations possible in the mountains.
The showers will diminish this evening as the low weakens and due
to loss of daytime heating. Another weaker upper low will move
into the northern Rockies and extend into our area on Saturday.
The shower coverage is expected to be much lower, mainly over the
higher terrain of southwest Idaho during the afternoon. The low
will also weaken and be replaced with drier northwest flow aloft
on Sunday. Temperatures will be a few degrees below normal today,
near normal on Saturday, and a few degrees above normal on Sunday.
Winds will be generally light through Saturday, with the
exception of locally breezy winds east of Mountain Home this

.LONG TERM...Sunday night through Thursday...Weak ridging aloft
brings a brief period of drier conditions into Monday.
Precipitation ahead of the next storm system will spread into
southeast Oregon by Monday afternoon and southwest Idaho by
Tuesday morning. This is a dynamic and moist system with
precipitable water values in the 90th percentile. Mild southwest
flow ahead of the system will raise snow levels to 6500-7500 feet
Monday night into Tuesday. The potential for moderate rainfall on
the remaining mid-elevation snowpack will warrant monitoring for
hydrologic impacts through midweek. Snow levels drop to 4500-5500
feet Tuesday night into Wednesday as the upper low crosses the
region. Conditions remain unsettled into Thursday under a
progressive westerly flow aloft. Temperatures are near normal
through Thursday.


.AVIATION...Mountains will see local MVFR and terrain obscuration
in rain/snow showers today with VFR in lower valleys. Isolated
thunderstorms this afternoon across southeast Oregon and in
vicinity of ID/NV border will bring potential for small hail and
gusty winds. Will see VFR conditions most areas after 30/03Z,
exception being local IFR in mountain valley fog. Surface winds to
15 kts with higher gusts in Snake Plain and ID/NV border region.
Winds aloft to 10k feet MSL: north-northwest 15-25 kts becoming 15
kts or less after 30/06Z

Weekend Outlook...Mostly VFR. Afternoon mountain showers
producing brief MVFR conditions on Saturday. Winds surface and
aloft to 10k feet MSL less than 15 kts through Sunday.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: A slight chance of snow showers before noon, then scattered rain and snow showers. Patchy fog before noon. Otherwise, mostly cloudy, with a high near 42. Light and variable wind. Chance of precipitation is 40%. Little or no snow accumulation expected. Partly cloudy, with a low around 26. Light and variable wind. A 20 percent chance of showers after noon. Sunny, with a high near 45. Calm wind.
Temperatures: 42 deg. F. 26 deg. F. 45 deg. F.
Wind direction: Variable Variable Calm
Wind speed: Light Light 0
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Scattered snow showers. Mostly cloudy, with a high near 31. Northwest wind around 6 mph. Chance of precipitation is 50%. Total daytime snow accumulation of less than a half inch possible. Partly cloudy, with a low around 24. North wind 5 to 7 mph becoming east after midnight. A 20 percent chance of snow showers after noon. Mostly sunny, with a high near 34. East wind around 5 mph becoming calm.
Temperatures: 31 deg. F. 24 deg. F. 34 deg. F.
Wind direction: NW N becoming East East
Wind speed: 6 5-7 5
Expected snowfall: Less than one half in. 0 in. 0 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.