THIS AVALANCHE ADVISORY EXPIRED ON March 7, 2019 @ 7:26 am
Avalanche Advisory published on March 6, 2019 @ 7:26 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Hazard is Considerable at all elevations. Up to 2 Feet of new snow by Friday along with gusty winds in the 20 MPH range are going to make Natural Avalanches possible and Human triggered avalanches likely. Use Good travel protocols like spreading out, and travel to avoid slopes steeper than 35 degrees. Lower elevation terrain, especially near rocks may produce small, loose-wet point releases, and or roller balls as the rain may creep up to 6,000 feet.

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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Winds are forecasted to gust around 23 MPH and blow in the range that is prime for transporting upwards of 2 feet of snow by Friday,  and loading lee slopes. This could create slabs up to 4 feet in depth by the end of the storm, Steep wind loaded terrain will be best avoided Today, and is going to be suspect in the near future. 

Avalanche Problem 2: Loose Wet
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Rain on snow in the lower elevations may cause wet loose slides today. Avoid steep saturated, especially rocky terrain. The rain line is forecasted to climb up to 6,000 feet. Friday, a cold front will help cool off the snow pack.

Avalanche Problem 3: Storm Slab
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Storm slabs will be building as we pick up around 2 feet of warm snow in the mountains by Friday. The snow that we have has produced natural avalanches, and was sensitive to skiers and riders for a bit after the storm...all the while since we have noticed the denser upper, 2 feet in the deepest places, snow pack to not have bonded well. There's are a lot of graupel mixed in, but the likely culprit was a mixture of surface hoar and or near surface facets that formed as a Cold front dropped temperatures quickly...now we will have another heavier denser layer on top of snow that has been struggling to bond. 

Use good travel protocols, and avoid terrain steep terrain.

advisory discussion

PAC will issue 3 Advisories per week through the remainder of the winter as long as funding is available. 

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. 

recent observations

Throughout the Council Mountain area yesterday, we observed quite a number of natural wind slab avalanches, and one large cornice fall. Our pits revealed a lot of graupel, but also some facets and some decomposing surface hoar. Slope cuts produced nothing but minor sluffing, and good riding conditions were found in the protected lower elevations where the snow was much deeper. South aspects picked up a good bit of heat occasionally, but the increasing clouds kept the snow a little cooler. Overall it was a warm day that made us think spring, and our snow pack is starting to reflect the change too. Warmth also was a likely player in the last natural avalanche cycle.

 

 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 24 deg. F.
Max. temperature in the last 24 hours: 24 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: 23 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

 

Area Forecast Discussion
National Weather Service Boise ID
315 AM MST Wed Mar 6 2019

.SHORT TERM...Today through Friday...
The first round of rain/snow associated with a Pacific warm front
has tracked northward through southeast OR and southwest ID.
Snow levels have been around 4500 feet MSL and will continue to
rise to 5000-6000 feet today. Shower coverage is expected to
increase late this morning into the afternoon hours as more
moisture and instability develop across the region. It is possible
that a few lightning strikes will accompany stronger showers in
the unstable atmosphere this afternoon, also allowing for
localized gusty outflow winds and brief heavy rain/snow.
Meanwhile, mountains above 5000-6000 feet will continue to see
additional light snowfall accumulations. Expect high temperatures
to climb above normal values today and Thursday associated with
this warm southwest flow. Precip will start to shift eastward and
enhance over southwest Idaho/Nevada border on Thursday ahead of an
approaching cold front. By early Friday morning, the cold front
will make its way southeastward and will promote colder
temperatures, low elevation snow levels, and breezy/windy
conditions across the area. Mountain snow showers will linger
throughout Friday.

.LONG TERM...Friday night through Tuesday...
Residual moisture will will combine with an area of low pressure
diving south along the Pacific coast to keep some mountain shower
activity possible through Sunday afternoon. Dry conditions
generally anticipated through Monday afternoon as most moisture
remains south of the area. However, an approaching trough will
move over the Pacific Northwest early Tuesday morning, sending
moisture into southeastern Oregon and southwestern Idaho. Models
in decent agreement with the placement of the precipitation
associated with this system, though have timing differences
related to the passage of the trough axis. Snow levels will
generally remain at or near valley floors, keeping most activity
as snow, or a rain-snow mix depending on temperatures. Overall,
temperatures look to remain 5 to 10 degrees below normal through
the period.

&&

.Aviation... Periods of MVFR. Widespread precipitation with
periods of IFR conditions possible. Snow levels around 5000-6000
feet MSL. Mountains will remain obscured. Isolated thunderstorms
possible after 18z Wednesday. Surface winds: South to southeast 5-10
kts increasing to 10-15 kts after 18z, with stronger wind possible
south of the Snake River Plain. Gusts of 20-30 kts possible. Winds
aloft at 10k feet MSL: West to southwest 25-35 kts.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow likely before noon, then rain showers. Some thunder is also possible. High near 39. South wind 3 to 7 mph. Chance of precipitation is 90%. Total daytime snow accumulation of less than a half inch possible. Showers and possibly a thunderstorm. Low around 32. South wind around 7 mph. Chance of precipitation is 90%. Snow showers likely, mainly before noon. Mostly cloudy, with a high near 35. Southwest wind 6 to 8 mph. Chance of precipitation is 70%. New snow accumulation of around an inch possible.
Temperatures: 39 deg. F. 32 deg. F. 35 deg. F.
Wind direction: South South SW
Wind speed: 3-7 7 6-8
Expected snowfall: less than one half in. 0 in. 1 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow before 11am, then snow showers after 11am. Some thunder is also possible. High near 28. South wind 10 to 14 mph, with gusts as high as 23 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 2 to 4 inches possible. Snow showers. Some thunder is also possible. Steady temperature around 25. South wind 13 to 15 mph. Chance of precipitation is 90%. New snow accumulation of 4 to 8 inches possible. Snow showers, mainly before 11am. High near 25. Southwest wind around 11 mph. Chance of precipitation is 80%. New snow accumulation of 3 to 7 inches possible.
Temperatures: 28 deg. F. 13-15 deg. F. 25 deg. F.
Wind direction: S S S
Wind speed: 10-14, Gusts 23 MPH 13-15 11
Expected snowfall: 2-4 in. 4-8 in. 3-7 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.