THIS AVALANCHE ADVISORY EXPIRED ON February 27, 2016 @ 5:22 am
Avalanche Advisory published on February 26, 2016 @ 5:22 am
Issued by George Halcom - Payette Avalanche Center
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The avalanche danger is MODERATE on upper elevation wind affected terrain today, and all slopes that receive direct sunshine. The possibility of loose/wet avalanches, Cornice failures, and small wet slab avalanches will increase today as temperatures warm throughout the day on steep southerly aspects.  Wind slabs that formed last week will make it possible to trigger an avalanche in steep, leeward terrain today.Low elevation and protected mid elevation slopes will have LOW danger today. 

How to read the advisory


  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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Above: Wet loose debris on a West aspect around 3PM. Below: West slide on the Soutwest face of Sgts Mtn near Brundage Resort

With temperatures climbing back into the upper 40's today, and mostly sunny skies, Expect a rise in loose/wet, roller ball and point release avalanche activity on steeper aspects affected by the sun and rising temperatures. The likelihood of loose wet slides continues to increase today with the higher than normal temps, and the danger of wet avalanche activity will continue to rise also. If you are seeing these red flags, move to cooler slopes in the afternoon.

 

Avalanche Problem 2: Cornice
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Large cornices have developed on many northerly aspects this winter and have already begun to fail, we noticed two natural slides on Thursday on shady North slopes just under the cornices, so keep your eyes open for what is above you.  As the temps climb, more of these big cornices are going to fail.  When the temperature climbs, you will need to find cooler slopes or call it a day. Stay far away from the edges of cornices as they can break a lot further back, and are quite large and tender right now.

Below is a natural avalanche that we noticed Thursday afternoon that had quite a bit of debris in it, triggered from a large chunck that fell off during the rising temperatures,, making the edge sometimes difficult to determine.

Avalanche Problem 3: Wind Slab
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The winds from last weeks storm did a great job of building wind slabs in the higher elevations of the advisory area. These slabs have been found on east, north and west facing aspects as well as slopes below rocky or steep headwalls. These slabs are stabilizing, but it could still be possible to trigger one in steep, rocky, terrain where weak/faceted spots exist near rocks,and or the slab is resting on a slick crust.

Some of these wind slabs formed on the crusts that developed during our last high pressure. Look for clues like cracking and collapsing as well as other obvious signs of wind slab like a textured or scalloped snow surface or pillows and drifts as you are moving through the mountains today. If you encounter a hollow, punchy, or drummy snow surface you are on wind slab.  Snowmobiles may have more of an affect on these slabs than skiers. Wind slabs often let you get well out on to them before they fail, leaving you in the middle of the slab when it is triggered. 

advisory discussion

Ladies, Don't forget about our Diva Avalanche Class this weekend at Tamarack Resort.  Show up early for yoga and coffee or come just for the class. Stay late for Happy Hour at Seven Devils Pub! Suggested donation of $10 for the Friends of the Payette Avalanche Center.

For more information or to RSVP email: hthiry@tamarackidaho.com

recent observations

Yesterday, we observed a couple Natural avalanches on shady North terrain in the fisher creek drainage that had been triggerred within the last 12" due to cornice failures from the daytime warming.

Based on our stability tests, and lack of recent avalanche activity, we are phasing the deep slab/persistent weak layer problem out of the advisory for now.  If (or when) temperatures allow melting water to percolate through the snowpack we could see this particular boogeyman make another visit to the West Central Mountains.  Keep this layer in mind if you are skiing or riding on protected northerly slopes with a steep, shallow snowpack because you could still be unlucky enough to find a trigger point for a large and unsurvivable avalanche. 

weather

Today will be the warmest day of the week with sunny skies and a high temperature in the upper elevations reaching around 48 degrees, and winds out of the Southwest 11-17 Mph. Tonight, we will see the snow line push all the way up to 7,000 feet before the temperatures drop 10 degrees by Saturday, which should bring the snow levels back down to 5,500 feet. Saturday will bring in the most snow, around 1-3 inches in the higher elevations.

 

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Mostly sunny, with a high near 44. Light south southeast wind. A 30 percent chance of rain after 11pm. Mostly cloudy, with a low around 32. South wind around 5 mph becoming calm in the evening. Rain showers before 11am, then rain and snow showers likely. High near 42. Light and variable wind becoming west 5 to 9 mph in the afternoon. Chance of precipitation is 100%. Little or no snow accumulation expected.
Temperatures: High 44 deg. F. Low 24 deg. F. High 42 deg. F.
Wind direction: South-Southeast South Variable-West
Wind speed: Light 5Mph-Calm 5-9 Mph
Expected snowfall: 0 in. 0 in. trace in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Mostly sunny, with a high near 48. Southwest wind 11 to 17 mph. A 40 percent chance of snow after 11pm. Mostly cloudy, with a low around 30. Breezy, with a south southwest wind 18 to 22 mph. New snow accumulation of less than one inch possible. Snow showers. High near 39. West wind 10 to 17 mph. Chance of precipitation is 100%. New snow accumulation of 1 to 3 inches possible.
Temperatures: High 48 deg. F. Low 30 deg. F. High 45 deg. F.
Wind direction: Southwest South-southwest South-southwest
Wind speed: 11-17 Mph 18-22 Mph 17 Mph
Expected snowfall: 0 in. less than one in. 1-3 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.