THIS AVALANCHE ADVISORY EXPIRED ON February 4, 2020 @ 7:30 am
Avalanche Advisory published on February 3, 2020 @ 7:30 am
Issued by George Halcom - Payette Avalanche Center
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The Avalanche Hazard is Considerable today.  Natural wind slab and loose wet avalanches are possible. Gusty 30 MPH winds and direct Sun will cause Natural avalanches. Human triggered wind slab and loose dry avalanches are likely.  Avoid wind loaded terrain, and be cautious of loose dry avalanches on steep, exposed, consequential slopes. 

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 have been not only cold, but gusting into the 30 Mph range since last night and are forecasted to do so through this afternoon from the North. The direction of winds have been mostly from the East. They started from the Northeast, and have swirled, East and Southeast...which is somewhat unusual for us to have Eastern winds.  Local terrain features are going to dictate where wind slabs will develop. 

Be cautious in the upper elevations near ridgeline, especially near cornices and just below cornices where the wind deposits snow and forms slabs that may be sensitive. 

If you are seeing shooting cracks, fresh avalanches, or see pillows and or sculpting, choose a different slope.

Avalanche Problem 2: Loose Dry
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Given all the loose dry snow and cold temperatures...A likely scenario is a skier or rider kicking loose a dry loose avalanche on slopes steeper than 35 degrees. Be cautious of the snow moving with you, especially in terrain that is consequential, and  sheltered from the wind where the snow is going to be looser and deeper.

In steep terrain today the Sun may naturally produce some point release/ loose-wet avalanches on South aspects...this should be pretty small. 

  

 

advisory discussion

*Snowmobiliers, the Granite Mountain closure went is in effect from January 15-March 31. Please respect Brundage Catski terrain closures which are CLEARLY marked on the west side of Goose Lake.  There is a shared use route at the northern end of the closure to allow access to Granite Mt Lookout and the upper east face of Granite Mt.  Additionally, public motorized use of ANY other Catski road is not permitted, including the roads between Brundage Reservoir and the East side of the Goose Lake Road in the Slab Butte and 76 areas. Please respect closed roads and areas and only ride on open roads and in open terrain.  There are also other areas that are closed to snowmobiling in the West Central Mountains. Click here for the Payette National Forest Winter Travel Map.

*Note to skiers accessing Jughandle Mountain from Silver Fox Trail.  Please park in signed areas only. Blocking or narrowing the road could result in loss of access to this area, ticketing or towing by Valley County.  There is NO parking allowed on the East side of the road or in the snowplow turnaround.  If you can't park in the signed area, park further down the road in a place where you are not obstructing traffic.

recent observations

Yesterday, we toured out to Sgt's Mtn, just North of Brundage Ski area and found a 7 foot snow pack and 23 cm, or 9 inches of new snow on a East aspect at 7300 feet. The new snow was sitting on graupel and a crust that had formed on the surface that is already halfway gone/degrading. The snow quality was good, and produced great skiing that traveled fast.

We were not able to get any failures to propagate in our tests. The winds were gusting strong at times enough to produce large plumes.

 Extended column test, no propagation...ECTN

 The few wind features that I kicked on on the ridges broke easily and started to entrain loose dry snow with them.

 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 3 deg. F.
Max. temperature in the last 24 hours: 16 deg. F.
Average wind direction during the last 24 hours: SE
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 31 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

 

Area Forecast Discussion
National Weather Service Boise ID
306 AM MST Mon Feb 3 2020

.SHORT TERM...Today through Thursday...
Hi-res models this morning continue to indicate a developing
convergence zone over the Magic Valley and Southwest Highlands.
This will bring about new snow accumulations, as well as blowing
and drifting snow, through late morning. In addition, this may
create a hazard to morning commuters as roads become slippery and
visibility is reduced. A Winter Weather Advisory remains in effect
for these areas through late morning. One detriment to this
forecast is the strong northwest winds in place across southern
Idaho, which could impact how far west the bands of snow are able
to reach. Northwest winds have been gusting 25-45 mph across
the area this morning, and are expected to peak by mid morning
before gradually subsiding this afternoon/evening. A Wind Advisory
remains in effect until 5PM MST for portions of southwest and
south-central ID. High temperatures today will remain below
normal with wind chills below freezing.

Cold and dry conditions are anticipated for Tuesday. Clouds will
increase Tuesday night ahead of a warm front that will introduce
precipitation to the area on Wednesday. Lower valleys will start
as snow with light accumulations possible before temperatures warm
above freezing throughout the day on Wednesday. The focus of
snowfall will be across the e-central Oregon and w-central Idaho
mountains that will persist into Thursday, and several inches of
new snow can be expected. Mountain valleys above 4000 feet MSL in
these areas could see 4-8 inches of new snow, while high mountain
elevations could see over 12 inches. Elsewhere, warm air
advection will start to nudge into the area from the west on
Thursday, supporting high temperatures 5-10 degrees above normal.

.LONG TERM...Thursday night through Monday...Moisture will continue
to flow southeast over mainly Baker County and the West-Central
Mountains Thursday night and Friday as temperatures remain 10 to 15
degrees above normal Friday. A strong upper level system will move
southeast across the area Saturday, bringing precipitation and a
significant cold front. Snow levels will fall from around 5000 ft
Friday afternoon to valley floors Saturday night. Lower elevation
snowfall accumulations are not expected to be significant because
moisture will be limited by the time the cold air arrives. Mountains
may see moderate snow. Snowfall will diminish to snow showers late
Sat night into Sunday, and occur mainly in the Boise Mountains and
along the ID/NV border. Monday will be mostly dry with temperatures
near normal.

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.AVIATION...Mostly VFR. MVFR to IFR conditions will occur in light
snow mainly east of a line from KMYL to KTWF. Mountains occasionally
obscured. Snow will taper off after 12z/Mon, except near KTWF and
KJER through 17z/Mon. Surface winds: NW 10-20 kt except 25-35 kt
with gusts up to 40 kt near KMUO KJER KTWF. Winds aloft at 10kft
MSL: NW-NE 25-35 kt.

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Sunny, with a high near 24. Wind chill values between zero and 10. North wind 7 to 9 mph, with gusts as high as 26 mph. Mostly clear, with a low around 3. North northwest wind 5 to 7 mph becoming calm in the evening. Increasing clouds, with a high near 23. Calm wind.
Temperatures: 24 deg. F. 3 deg. F. 23 deg. F.
Wind direction: N NNW Calm
Wind speed: 7-9 5-7 becoming calm 0
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Sunny, with a high near 13. Wind chill values between -5 and -11. North wind 11 to 16 mph, with gusts as high as 32 mph. Mostly clear, with a steady temperature around 6. Wind chill values between -7 and -12. North northeast wind 5 to 10 mph, with gusts as high as 22 mph. Increasing clouds, with a high near 14. Wind chill values between -9 and 1. North wind around 5 mph becoming calm in the morning.
Temperatures: 13 deg. F. 6 deg. F. 14 deg. F.
Wind direction: N NNE N
Wind speed: 11-16 Gusting to 32 MPH 5-10 Gusting to 22 MPH 5 MPH becoming calm
Expected snowfall: 0 in. 0 in. 0 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.