THIS AVALANCHE ADVISORY EXPIRED ON February 20, 2016 @ 7:16 am
Avalanche Advisory published on February 19, 2016 @ 7:16 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The avalanche danger today is CONSIDERABLE for wind loaded  aspects above 7,000 feet. Below 7,000 feet, the avalanche danger is MODERATE. A foot of new snow ,over the last 24 hours, came in with 30 MPH winds  out of the SE, S, and mostly Southwest creating wind slabs that are possibly reactive to the weight of a rider or skier. A slick rain crust lies just beneath the new snow, and has not bonded as well on South aspects.

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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Yesterday we could see plumes of snow shooting off the tops of the peaks growing wind slabs on Northern, and East aspects. The winds out of the South, Southwest got up to 30MPH, and were moving the fresh 10 inches of light snow. Today, we are forecasted to recieve strong winds again out of the South upwards of 44MPH along with another 1-3 inches of snow....expect wind slabs on Northern, and East aspects near ridgelines and other features that get cross-loadeed...Southern aspects are showing less bonding strength in the new snow than other aspects, and will have areas with slabs resting on the slick rain crust.

Avalanche Problem 2: Loose Dry
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Yesterday, were happy to come into 10 inches of dry snow that wanted to travel with us in steeper terrain. With another 5 inches last night, and 1-3 more today, you may have some loose snow moving with you, or sluffing in terrain steeper than 35 degrees that poses a threat to knock you off course in sustained, longer lines. The new snow has a higher pootential of running on South aspects where it lies on our old slick rain crust.

Avalanche Problem 3: Deep Slab
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We are still finding, what will probaly be a permanint problem for our snowpack: buried surface hoar. Triggering a slab due to this weak layer has become more difficult over the last two and a half weeks, but I would not let my guard down, We are still finding this weak layer in upper elevation wind protected terrain. Pit results and stability testing are pointing toward less likelihood of triggering, but if triggered we are still talking about a potentially unsurvivable hard slab avalanche. Take the time to carefully assess terrain choices on the north half of the compass today. Especially areas where the snow cover is thinner which allows the buried surface hoar to be closer to the surface, and in turn more reactive---especially for snowmachines. This is the same layer that was the cause of the fatal avalanche on January 31st. A persistent weak layer such as this is a low probablility, but HIGH CONSEQUENCE scenario.  In addition, the old snow layer around 55cm is still showing signs of instability in our pit tests with moderate test scores.  This layer is comprised of grauple in some areas and has buried Surface Hoar and fine grained facets mixed in in other areas.

advisory discussion

 

BACKCOUNTRY FILM FESTIVAL!

Come join Friends of Payette Avalanche Center, McCall Winter Sports Club, and Brundage Mountain to celebrate this weekends powder skiing with a night of backcountry films.

Tomorrow night at McCall Golf Course Clubhouse!

Doors open at 6 pm and the show will start at 7 pm.

Please come out and share your stoke!

recent observations

Conditions have improved, and the snowpack is trying to re-freeze where it has not yet. Yesterday, we toured North of Brundage, out to Fisher Cr Saddle and found dry snow, almost a foot above 7500 feet. The winds were doing a great job pushing the snow around.  The rain crust is supportable, and is bonding, but not as well on South aspects. We noticed shallow wind slabs forming on Northern aspects.

weather

Today, we will see a high temperature in the upper elevations around 32 degrees, and strong winds out of the South ramping up to 44 MPH with new snow totaling around 1-3inches above 5500 feet. Tonight, we should have a low of 17 degrees in the upper elevations with 1-3 inches of additional snow along with winds forecasted out of the Southwest gusting upwards of 44 MPH, and winding down around midnight as a brief cold front pushes in which should bring the snow levels back down to 3,000 feet by Saturday morning. 

 

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Snow showers before noon, then rain and snow showers likely. High near 39. South wind 5 to 11 mph. Chance of precipitation is 80%. New snow accumulation of less than one inch possible. Rain and snow showers before midnight, then a chance of snow showers. Low around 22. South wind 6 to 11 mph becoming light after midnight. Chance of precipitation is 90%. New snow accumulation of less than a half inch possible. A 20 percent chance of snow showers before noon. Mostly cloudy, with a high near 34. South southwest wind 3 to 5 mph.
Temperatures: High 39 deg. F. Low 22 deg. F. High 34 deg. F.
Wind direction: South South South/Southwest
Wind speed: 5-11MPH 6-11 MPH becoming light 3-5 MPH
Expected snowfall: Less than one inch in. less than half in. Less than half an inch in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Snow showers. High near 32. Windy, with a south wind 20 to 30 mph, with gusts as high as 44 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible. Snow showers, mainly before 11pm. Low around 17. Windy, with a southwest wind 25 to 30 mph decreasing to 13 to 18 mph after midnight. Winds could gust as high as 44 mph. Chance of precipitation is 100%. New snow accumulation of 1 to 3 inches possible. A 50 percent chance of snow showers, mainly before 11am. Mostly cloudy, with a high near 28. Southwest wind 9 to 13 mph. New snow accumulation of less than a half inch possible.
Temperatures: High 32 deg. F. Low 17 deg. F. High 28 deg. F.
Wind direction: South Southwest Southwest
Wind speed: 20-30 gust to 44MPH 25-30 gusts to 44MPH! 9-13 MPH
Expected snowfall: 1-3 in. 1-3 in. Less than one half 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.