THIS AVALANCHE ADVISORY EXPIRED ON January 23, 2016 @ 6:53 am
Avalanche Advisory published on January 22, 2016 @ 6:53 am
Issued by -
bottom line

The Avalanche Danger remains CONSIDERABLE on upper elevation terrain, especially slopes that are steep and have been wind loaded. Skiers or riders could trigger recently formed wind slabs in exposed terrain. At middle and lower elevations the Avalanche Danger is MODERATE. This is due to wind loading being less prominent and the wind slabs being smaller and less reactive. 

 

How to read the advisory


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

Wind slabs and wind loaded terrain continue to be the primary concern.  Over the past few days the mountains have picked up another 4-5 inches of snow and a few more inches are expected today. The new snow combined strong winds out of the south and southwest today will make areas that are already suspect even more sensitive.  These 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
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

While time heals everything, our current persistent weak layers are doing so slowly. 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 8-10 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 class 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

We had a report of a human triggered avalanche at Duck Lake from Wednesday, January 20th. The slide was reported to have been set off from above and no one was involved. PAC forecasters were at Duck Lake yesterday and found a recent avalanche that met the description of the human triggered slide. It was on a north-northeast aspect at 7,300 feet and failed on buried surface hoar. The avalanche size was a R3D2 and was approximately 200 feet wide and ran about 100 vertical feet through trees and over rocks with a crown measuring 24 inches. While not huge, this slide could and would bury a person. For pictures and more details check out our OBSERVATION page or FRIENDS OF PAYETTE AVALANCHE CENTER Facebook page.

Please help us by reporting any human or natural avalanches via our OBSERVATION tab above. We need you!

weather

Today we will see 1-3 inches of new snow fall in the mountains with temps reaching low 30's. This snow will be accompanied by strong winds out of south-southwest ranging from 20-30 MPH and gusting to near 50 MPH. For the weekend, it looks to be more of the same. A few inches of snow possible each day, with moderate winds out of the south-southwest. The brunt of this current storm will be heading to our south. The next large storm is still expected at the end of next week, but confidence is low.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: A 50 percent chance of snow showers after 11am. Patchy fog before 11am. Otherwise, cloudy, with a high near 34. Calm wind becoming south around 6 mph in the afternoon. Total daytime snow accumulation of less than a half inch possible. A 40 percent chance of snow. Cloudy, with a low around 28. South wind around 5 mph becoming calm in the evening. New snow accumulation of less than a half inch possible. Rain and snow, becoming all snow after 11am. High near 34. Calm wind becoming south around 6 mph in the afternoon. Chance of precipitation is 90%. New snow accumulation of less than one inch possible.
Temperatures: High 34 deg. F. Low 28 deg. F. High 34 deg. F.
Wind direction: south south south
Wind speed: calm calm 6
Expected snowfall: less than half an inch in. less than half an inch in. Less than one inch in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Snow showers, mainly after 11am. High near 34. Windy, with a south southwest wind 22 to 32 mph, with gusts as high as 48 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 3 inches possible. A 50 percent chance of snow. Cloudy, with a temperature rising to around 33 by 3am. Breezy, with a south southwest wind 16 to 20 mph, with gusts as high as 29 mph. New snow accumulation of 1 to 2 inches possible. Snow. Temperature falling to around 24 by 4pm. Breezy, with a southwest wind 18 to 22 mph, with gusts as high as 32 mph. Chance of precipitation is 100%. New snow accumulation of 2 to 4 inches possible.
Temperatures: High 34 deg. F. 33 deg. F. Falling to 24 deg. F.
Wind direction: south-southwest south-southwest southwest
Wind speed: 22-32 gusts to 48 16-20 gusts to 29 18-22 gusts to 32
Expected snowfall: 1-3 in. 1-2 in. 2-4 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.