THIS AVALANCHE ADVISORY EXPIRED ON January 22, 2016 @ 7:04 am
Avalanche Advisory published on January 21, 2016 @ 7:04 am
Issued by -
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The Avalanche Danger remains CONSIDERABLE on upper elevation terrain, especially slopes that are steep and have been wind loaded. Buried weak layers on protected aspects will also make it possible to trigger avalanches in non wind affected terrain. Careful snowpack evaluation, cautions route-finding and conservative decision making are essential during these times of instability. Below 7,000 feet the Avalanche Danger is MODERATE due to human triggered avalanches being possible.

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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Wind slabs and wind loaded terrain continue to be the primary concern.  Over the past 24-36 hours the mountains have picked up another 4-5 inches of snow. The new snow combined with moderate to strong winds out of the southeast, south and southwest are adding more snow in areas that are already suspect.  Sensitive wind slabs may be found on southeast, east, northeast, north, northwest,and west facing terrain. Wind slabs are widespread in the upper elevations and range in sensitivity from easily triggerable to resistant. They also range in size from a few inches to a few feet in some areas. New snow over the last few days has also done a great job camouflaging some of the wind slabs formed earlier this week, so you may not see any visual clues. These slabs range in density between soft to hard which means they may let you get well out onto them before they fail.  We have been intentionally triggering relatively large avalanches with relatively small cornice bombs in these areas which means they are more likely to fail under a skier or snowmobiler.  Also, some of these wind slabs may be resting on a layer of  weak, faceted snow or surface hoar that was buried last week.  Your best bet until our snowpack begins to 'heal' is to avoid skiing or riding on or below steep, wind loaded slopes.

Avalanche Problem 2: Persistent Slab
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Several different weak layers formed on or near the snow surface during the last period of high pressure and are lurking in our snowpack right now.  These persistent weak layers have slowly been covered over the last 8 days and have failed in some areas, and are still waiting for a trigger in other places.  These layers include buried surface hoar and near surface faceted snow on shadier aspects and a series of unsupportable and supportable crusts on the southerly (solar) aspects. If you take 5 minutes to dig into the snow right now, you can see exactly where these layers are, they are pretty obvious in the snowpack. You can see 2 different layers in the crown in the photo below, the upper is the wind and storm slab and the lower is the buried surface hoar. Buried surface hoar and faceted snow have the ability to propagate over large areas when they fail and are responsible for most avalanche incidents and fatalities.

advisory discussion

Don't forget to check PAYETTEAVALANCHE .ORG for upcoming events!

*Saturday January 23rd- SLEDUCATION  This is an Avalanche Awareness classed specifically for snowmobilers who are traveling into avalanche terrain.

*Saturday January 30th- OUT OF BOUNDS SAFETY Are you riding the lifts up at the ski are and then heading into the backcountry? This class is for you!

*Saturday February 13th- FRIENDS OF PAYETTE AVALANCHE CENTER ANNUAL FUNDRAISER Do you check the avalanche forecast before heading out in to the backcountry? Would you like to see the weather stations up and running(and more weather stations? If you answered yes, then come out to Little Ski Hill and help support the Payette Avalanche Center! There will be skiing,beer, food, door prizes, and silent auction items up for the taking. This is a family friendly event. Come out an support the Avalanche Center, we can't do this with out you!

 

recent observations

It was a day of traveling in the metaphorical ping pong ball yesterday, so it was hard to see if any more natural avalanches had occurred. We have had no new reports of human or natural avalanches in our advisory area over the last 24 hours, however, I believe that has more to do with visibility that stability. If there is a break in the clouds today expect to see avalanche activity on many steep slopes above 7,000 feet on west-southeast aspects.

Here are a few pictures from Lick Creek from earlier this week (photo credit: Ride McCall's Facebook page).  Please take the time to send us an email if you see or trigger avalanches in the area. You can also send us your observations and photos through our website by clicking on the Observations tab.  This information is vital to PAC forecasters and may help save a life.

 

weather

Today through Friday a weak warm front is making its way through the advisory area causing cloudy skies and a slight chance of snow. Temps will be above normal and should reach into the mid 30's at higher elevations with winds out of the southwest blowing 15-25 MPH and gusting into the low 30's. Next chance for measurable snow fall will be Friday afternoon into Saturday morning. This next shot of snow will not be anything to write home about, but a more active weather pattern is expected late next week potentially bringing several days of precipitation to the advisory area. 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Thursday Thursday Night Friday
Weather: Patchy fog before 11am. Otherwise, cloudy, with a high near 34. Light south southeast wind. Cloudy, with a low around 23. Light southeast wind. A slight chance of rain and snow before 11am, then a chance of snow. Cloudy, with a high near 36. Calm wind becoming south 5 to 7 mph in the afternoon. Chance of precipitation is 40%. New snow accumulation of less than a half inch possible.
Temperatures: 34 deg. F. Low 23 deg. F. 36 deg. F.
Wind direction: south-southeast southeast south
Wind speed: light light 5-7
Expected snowfall: 0 in. 0 in. less than half inch in.
Granite Mountain at 7700 feet.
  Thursday Thursday Night Friday
Weather: Cloudy, with a high near 34. Breezy, with a south southwest wind 18 to 22 mph, with gusts as high as 32 mph. Cloudy, with a low around 25. Breezy, with a south southwest wind 23 to 25 mph, with gusts as high as 37 mph. A 50 percent chance of snow, mainly after 11am. Cloudy, with a high near 33. Windy, with a south southwest wind 25 to 30 mph increasing to 32 to 37 mph in the morning. Winds could gust as high as 55 mph. New snow accumulation of 1 to 3 inches possible.
Temperatures: 34 deg. F. low 25 deg. F. 33 deg. F.
Wind direction: south-southwest south-southwest south-southwest
Wind speed: 18-22, gusting 32 23-25, gusting 37 25-37, gusting 55
Expected snowfall: 0 in. 0 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.