THIS AVALANCHE ADVISORY EXPIRED ON February 3, 2017 @ 5:10 am
Avalanche Advisory published on February 2, 2017 @ 5:10 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The avalanche danger today is MODERATE on steep, wind affected slopes above 7000 feet due to human triggered avalanches being possible. Below 7000 feet the avalanche danger is LOW.  Do keep in mind that a layer of buried surface hoar, and basal facets are still being tracked around the advisory area. While the chances of triggering an avalanche due to this problem is low, the consequences would be high.

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
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Thin Wind slab on the snow surface Feb, 1st on the West Face of Bruin around 8,000 feet

Winds have calmed down, but moderate winds gusting upwards of 24MPH out of the South-southwest around Tuesday, and a few new inches of snow helped form newer wind slabs up to 6 inches thick in the upper most terrain on the north half of the compass. These new wind slabs may be resting on a slick crust that has developed in the last week from the Sun, and may be sensitive to the weight of a skier or rider. Be cautious in steep exposed terrain, where a small wind slab could knock you off your feet.

Older wind slabs can still be found, but should be very stubborn to trigger. However, once triggered any avalanche can grow into a bigger problem if it breaks into weaker snow. Your best strategy is to simply avoid fat looking, rounded pillows of snow, especially if they feel or sound hollow like a drum.

Avalanche Problem 2: Persistent Slab
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The upper ridgelines, where it is rocky, is harboring some basal facets. Yesterday we found a big (6 inch) layer of basal facets with a 2 foot slab resting on top of it in a pit at 8400 feet on the West aspect of Bruin. Our stability tests came out with hard results failing near the ground (CT24, and an ECTN). While our stability tests showed hard to trigger, this would be a large cosequence. Our long spell of cold weather probably brought teperatures close to -40F near the ridelines, producing this layer of facets near the ground.

Rocky thin, upper elevation West slope of Bruin around 8kft, has ony a few feet of snow or less in spots where the rocks are barely covered

Future avalanche problems may arise from this bad recipe, even though the facets are showing signs or strength/rounding you are most likely to trigger this layer in a thin, rocky area near the ridgelines ---around 8,000 feet. Check out this video of our pit. 

advisory discussion

We are still tracking buried Basal facets, surface hoar, and near surface facets that are now buried in our snowpack. These persistent grain types can awaken after being dormant for an extended period of time (hence the name persistent). While we don't have them as an avalanche problem, keep this layer in mind as you make your travel plans for the day. The layer is most likely to be found on any slopes with a north tilt to them, in middle and upper elevations. Areas to be especially weary of are those that were not impacted by the winds (sheltered) previous to our last big load of snow.

**Before committing to skiing or riding a slope over 30 degrees take a moment to dig into the snow and see if a thin grey line (buried surface hoar) is buried one to two feet below the snow surface. If so, look elsewhere to ski and ride.

The Friends of the Payette Avalanche Center (FPAC) needs YOU! We are in desperate need of more user support and financial assistance. The avalanche forecast is not a guaranteed service, and is in jeopardy of dwindling down to only a couple of days a week in the near future. Please help if you can by clicking the DONATE tab above. If you value this life saving information, make a donation or help the FPAC in raising funds for the future.

Snowmobiler/Snowbiker Travel Restrictions:  a quick reminder that the Granite Mountain Area Closure is now in effect.  In addition there are other areas on the Payette National Forest that are CLOSED to snowmobile traffic including Jughandle Mt east of Jug Meadows, Lick Creek/Lake Fork Drainage (on the right side of the road as you are traveling up canyon), and the area north of Brundage Mt Ski area to junction "V" and along the east side of Brundage and Sergeants' Mts. with the exception of the Lookout Rd( junction "S").  Please respect these closures and other users recreating in them.  Winter Travel Map(East side). You can download the map to the AVENZA app on your phone, and know your exact location while you are out riding. 

recent observations

Yesterday, above Upper Hazard Lake, on Bruin, we observed some Southwest slopes releasing loose, point releases in the new 3-6 inches of snow. We also observed wind effect on the snow surface, a shallow wind slab resting on the surface of the snow, and a big (6 inch) layer of basal facets with a 2 foot slab resting on top of it in a pit at 8400 feet on the West aspect of Bruin. Our stability tests came out with hard results failing near the ground (CT24, and an ECTN). While our stability tests showed hard to trigger, this would be a large cosequence. Our long spell of cold weather probably brought teperatures close to -40F near the ridelines, producing this layer of facets near the ground. Future avalanche problems may arise from this bad recipe, even though the facets are showing signs or strength/rounding you are most likely to trigger this layer in a thin, rocky area near the ridgelines ---around 8,000 feet. Check out this video of our pit.

 

 

 

 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 14 deg. F.
Max. temperature in the last 24 hours: 16 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 14 mph
New snowfall in the last 24 hours: 2 inches
Total snow depth: inches
weather

The mountains picked up around an inch of new snow overnight. Granite Mountain weather station is reporting 14 degrees with light winds out of the west-southwest as of 5 am. Today we will get a little Snow. High near 21. Wind chill values between zero and 10. West southwest wind 6 to 10 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 2 inches possible. we will have light winds out of the North-northwest becoming calm. Temperatures will be in the 20's and forecasts are calling for only around a half an inch of new snow in the mountains. Friday looks to be a serious storm with a good amount of snow and 55MPH gusts!

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Thursday Thursday Night Friday
Weather: Snow likely. Cloudy, with a high near 26. Light west southwest wind. Chance of precipitation is 70%. New snow accumulation of less than one inch possible. Snow likely, mainly after 11pm. Cloudy, with a low around 16. Calm wind becoming southeast around 5 mph after midnight. Chance of precipitation is 70%. New snow accumulation of less than one inch possible. Snow. High near 33. South wind 6 to 10 mph. Chance of precipitation is 90%. New snow accumulation of 2 to 4 inches possible.
Temperatures: high 26 deg. F. low 16 deg. F. high 33 deg. F.
Wind direction: West-southwest Calm-SE South
Wind speed: light 5 6-10
Expected snowfall: less than one half in. 1-2 in. 1-2 in.
Granite Mountain at 7700 feet.
  Thursday Thursday Night Friday
Weather: Snow. High near 21. Wind chill values between zero and 10. West southwest wind 6 to 10 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 2 inches possible. Snow likely, mainly after 11pm. Cloudy, with a low around 18. Breezy, with a south southwest wind 5 to 10 mph increasing to 16 to 21 mph after midnight. Chance of precipitation is 60%. New snow accumulation of 1 to 2 inches possible. Snow. High near 27. Windy, with a south southwest wind 23 to 28 mph increasing to 34 to 39 mph in the afternoon. Winds could gust as high as 55 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 7 inches possible.
Temperatures: high 21 deg. F. low 18 deg. F. high 27 deg. F.
Wind direction: West-southwest South-southwest Southwest
Wind speed: 6-10 16-21 34-39 Gusting 55MPH
Expected snowfall: 1-2 in. 1-2 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.