Avalanche Advisory published on January 29, 2020 @ 6:39 am
Issued by Dave Bingaman - Payette Avalanche Center
bottom line

The upper elevation avalanche hazard is Considerable today.  Expect to see storm slabs of between 1 and 2 feet where the new snow is not bonding to the older snow below.  A combination of heavy snow  and wind over the last few days and wind have created the potential for human caused avalanches on steeper terrain.  Sensitive wind slabs will likely be found near ridgelines and other wind affected areas. 

How to read the advisory

  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Storm Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Local Snotel sites added between .6 and 1 inch of new Snow Water Equivalent(SWE) yesterday with another 8-10 inches of snow reported at Brundage and Tamarack over the last 24 hours. Temperatures started out pretty warm yesterday morning with rain in the lower valley.  Cooling throughout the day lowered the snow line to about 4500 ft by mid afternoon. The effect was predictable with avalanches on steep terrain occurring naturally in the new snow layers.  The avalanche hazard should be confined to these storm slabs in the upper 1-2 feet of the snowpack, expect that to be slightly deeper in the upper elevations.  Play it safe today, avoid steep slopes and utilize good travel protocols while you enjoy the deep snow.


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

Expect to see recently formed wind slabs on a variety of upper elevation slopes.   Winds have been out of the NE, N and NW throughout the last 24 hours with gusts reaching into the high teens.  Given the amount of snow we have received over the last few days and the fairly steady amount of wind, you could see wind sensitive wind slabs anywhere from a few inches to over 2 feet.  Look for these near ridgetops, under corniced ridgelines and even in exposed terrain in the middle elevations.  In your face signs like cracking under your skis or snowmobile, a sudden change in how far your skis or sled are sinking in (ski/sled penetration) or visual clues like obvious drifting or sculpted snow  are all great indicators of wind slabs.  Avoid traveling in these areas and avoid growing cornices as well, some cornices are getting pretty large and can fail further back than you expect.

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.  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

Several reports of natural avalanches came in yesterday, patrollers at Tamarack found sensitve wind slabs under the cornices near the top of the ridge yesterday morning and some local snowmobilers found steep rollovers had slid naturally.  Deep conditions exist off trail and in the upper elevations, keep your eyes on your partners while you are travelling through the mountains today.  Improving visibility and a drying trend today should allow for a good inspection of steeper terrain, if you see natural avalanches please take a picture and report them on our observations page.  It is very easy and can contain basic information like elevation, aspect and time or more detailed information about the snowpack.




CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 19 deg. F.
Max. temperature in the last 24 hours: 26 deg. F.
Average wind direction during the last 24 hours: N
Average wind speed during the last 24 hours: 6 mph
Maximum wind gust in the last 24 hours: 19 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches

.SHORT TERM...Today through Saturday...Clearing skies have allowed
patchy valley fog to develop overnight, including the Boise area.
The fog will likely expand further and include portions of the
Lower Treasure Valley this morning. The fog may be locally dense.
Dry conditions will prevail through most of today within a
northerly flow aloft. Light precipitation (rain with snow above
around 4000 feet) associated with a weakening upper trough will
enter from the northwest later this afternoon and progress across
the area tonight. Snowfall totals of 1 to 2 inches are expected
above 4000 feet. Drier conditions return by Thursday afternoon as
an upper ridge builds in from the west. A warm front will bring a
chance of precip across the north Thursday night through Friday.
Snow levels will rise from around 3500 feet Thursday night to
around 5000 feet Friday afternoon. Precip amounts will be light.
Westerly flow aloft will bring dry conditions across southeast
Oregon and southwest Idaho Friday night through Saturday, along
with mild temperatures on Saturday. Temperatures will trend
slightly warmer each day, with Saturday the warmest of the week
with highs in the 50s across the lower valleys.

.LONG TERM...Saturday night through Wednesday...An upper level
trough pushes through the area Saturday night into Sunday bringing
widespread rain and snow for the area. Snow levels begin around
6500 feet MSL then drop as the cold front pushes through Sunday
afternoon reaching valley floors by Sunday evening. A ridge of
high pressure shifts a bit further to the east for Monday and
Tuesday giving us a cool northwest flow. Temperatures hover close
to normal for these periods. By Wednesday morning, a warm frontal
boundary makes its presence felt bringing widespread rain and
snow back into the region. Snow levels climb back up to around
4500 feet MSL for much of the area by the end of the period,
except for the central Idaho mountains where levels remain around
3000 feet MSL.


Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Patchy fog before 11am. Otherwise, increasing clouds, with a high near 32. Calm wind. Snow, mainly before 11pm. Steady temperature around 27. Calm wind. Chance of precipitation is 90%. New snow accumulation of less than one inch possible. Partly sunny, with a high near 35. Calm wind.
Temperatures: 32 deg. F. 27 deg. F. 35 deg. F.
Wind direction: Calm Calm Calm
Wind speed: Calm Calm Calm
Expected snowfall: 0 in. Trace in. 0 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Increasing clouds, with a high near 24. Calm wind becoming south southwest 5 to 7 mph in the afternoon. Snow, mainly before 11pm. Low around 20. South southwest wind 5 to 8 mph becoming calm after midnight. Chance of precipitation is 100%. New snow accumulation of 1 to 2 inches possible. Partly sunny, with a high near 29. Light and variable wind.
Temperatures: 24 deg. F. 20 deg. F. 29 deg. F.
Wind direction: SW SSW Light
Wind speed: 5-7 5-8 Variable
Expected snowfall: 0 in. 1-2 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.