Avalanche Advisory published on January 27, 2020 @ 7:20 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Danger is MODERATE above 7,000 feet.  Natural avalanches are unlikely but human triggered avalanches remain possible.  Shallow wind and storm slabs are possible on leeward slopes.  You may also trigger avalanches on layers buried from 1 foot to several feet. 

How to read the advisory

  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Storm Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Fluctuating temperaures from our warmest day have formed a couple layers in the upper 1-2 feet of the snowpack that are not bonded as much as you would like but have not shown any cracking and lacked propagation. The heavier upper new snow was producing large rollerballs on the snow surface yesterday naturally and while skiing steep slopes.

More snow and wind over the next 24 hours are likely form storm slabs that fail 1-2 feet deep...Steep slopes should be suspect and stll aproached with good sound travel protocols like spreading out and going one at a time.

Avalanche Problem 2: Wind Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

The winds have been a bit lighter recently, but gusting around 18 MPH. Fresh wind slabs 6-12 inches deep are likely on exposed slpoes.  Over the next 24 hours the West Central mountains are forecasted to recieve over a foot of new snow with slightly warming temperatures, and Winds are forecasted to increase into the moderate range which can account for the majority of wind slab formation on lee slopes just below ridgelines.

Wacth for obvius signs like sculpting, hollow sounding snow, pillows, and shooting cracks.

advisory discussion

*Snowmobiliers, the Granite Mountain closure went into effect on Janurary 15.  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.  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 in the Lick Cr drainage, above Duck Lake, we watched the snow change from the warmest day yet in the mountains. Our test pit on an NE facing slope at 7800 feet revealed a couple layers that are struggling to bond with facets and graupel. No propagation on the two layers 6-12 inches down from the surface was observed, and we could not get any cracks to propagate. The warmup made the surface sensitive enough to produce some pretty big rollerballs naturally as well as from our ski turns. We were able to get a small NE storm slab pocket to fail in the new snow and run small while skiing above it. Un-supported rollovers were failing easily, but not spreading out with ski cuts in the 2 layers just below the surface.


NE aspect of South Rain, 7800 feet...the upper layers failing moderately CT 11, and 13

 The snow was getting heavier, but still skiing and riding well.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 20 deg. F.
Max. temperature in the last 24 hours: 29 deg. F.
Average wind direction during the last 24 hours: NE
Average wind speed during the last 24 hours: 8 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

Area Forecast Discussion
National Weather Service Boise ID
324 AM MST Mon Jan 27 2020

.SHORT TERM...Today through Thursday...Skies cleared just long
enough for patchy dense fog to form in some valley locations
overnight. Increasing clouds are already improving the foggy
conditions in some areas, and further improvement is likely this
morning as the clouds continue to stream in from the west.

Light precipitation will move into most of southeast Oregon and
southwest Idaho today ahead of the next upper trough. Steadier
precip will develop tonight as the trough moves closer, favoring
the higher elevations in the north (generally north of Burns-
Boise). The precip will spread further south on Tuesday as the
trough moves through the region. Snow levels will generally range
from 4000 to 5000 feet for the duration of the event. Several
inches of snowfall are expected above 5000 feet in Baker County
and central Idaho. The precip will diminish Tuesday night within a
drier northerly flow aloft, which will continue through
Wednesday. A weaker upper trough will be accompanied by a chance
of light precipitation Wednesday night through Thursday, once
again favoring the northern areas. Snow levels of 3000-4000 feet
will climb to 4000-6000 feet by Thursday afternoon. Temperatures
will remain 5 to 10 degrees above normal.

.LONG TERM...Thursday night through Monday...An upper level ridge
builds off the west coast to begin the period sending the storm
track to our north. Isolated activity will impact our northern
zones during this time period. Snow levels sit around 6500 to 7000
feet MSL during the first half of the extended forecast period.
By early Sunday morning the ridge pushes further south allowing
for an upper level trough to drop into the Pacific Northwest.
Widespread showers move in Sunday afternoon into late evening with
snow levels dropping rather rapidly behind the cold front. By
Monday morning, snow levels are at valley floors. Temperatures
begin above normal then become close to normal by Monday.


.AVIATION...IFR/LIFR in valley fog through late morning. Isolated
showers will impact sites throughout the day with areas north of
a KBNO-KEUL-KSUN line seeing the highest probabilities. Snow
levels sit between 3500 to 4000 feet MSL. Surface winds, southwest
to southeast 5-10kts. Winds aloft to 10k feet MSL, west 30-35kts.


Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Snow likely, mainly before 11am. Mostly cloudy, with a high near 32. Light south southwest wind. Chance of precipitation is 60%. Total daytime snow accumulation of less than a half inch possible. Snow likely, mainly after 11pm. Cloudy, with a low around 28. Light south wind. Chance of precipitation is 60%. New snow accumulation of 1 to 2 inches possible. Snow. High near 35. South wind 3 to 6 mph. Chance of precipitation is 100%. New snow accumulation of 2 to 4 inches possible.
Temperatures: 32 deg. F. 28 deg. F. 35 deg. F.
Wind direction: SSW S S
Wind speed: Light Light 3-6
Expected snowfall: less than one half in. 1-2 in. 2-4 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Snow likely, mainly before 11am. Mostly cloudy, with a high near 21. South southwest wind 5 to 9 mph. Chance of precipitation is 70%. Total daytime snow accumulation of 1 to 2 inches possible. Snow. Temperature rising to around 25 by 2am. South wind 9 to 11 mph. Chance of precipitation is 80%. New snow accumulation of 3 to 5 inches possible. Snow. High near 26. South southwest wind 9 to 11 mph. Chance of precipitation is 100%. New snow accumulation of 4 to 8 inches possible.
Temperatures: 21 deg. F. 25 deg. F. 26 deg. F.
Wind direction: SSW S SSW
Wind speed: 5-9 9-11 9-11
Expected snowfall: 1-2 in. 3-5 in. 4-8 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.