THIS AVALANCHE ADVISORY EXPIRED ON January 10, 2017 @ 6:37 am
Avalanche Advisory published on January 9, 2017 @ 6:37 am
Issued by Kent May - Payette Avalanche Center
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The avalanche danger today is HIGH in elevations above 7,000 feet. Human triggered avalanches are VERY LIKELY on steep, wind drifted slopes, especially those facing the north half of the compass. Once triggered, today's avalanches have the potential to break deep/wide, resulting in a dangerous avalanche.

CONSIDERABLE avalanche danger exists on steep wind drifted slopes at mid elevations and human triggered avalanches are likely.

Below 6,000 feet MODERATE avalanche danger exists and human triggered slides are possible.

How to read the advisory


  • Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
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A warm, wet, windy system is affecting our region and it's currently pretty sketchy out there and will continue to be over the next few days. Due to the strong winds and snow available for transport, I suspect drifting is occurring in unusual locations and lower down slope than we normally see. As the storms continue to materialize over the next few days, avalanches will begin breaking much deeper and wider than you might expect. Triggering an avalanche right now could cause a large and unsurvivable slide. If you do go out today, you will want to steer clear of steep, wind drifted terrain and be on the look out for and avoid any rounded, fat, pillows of snow, especially if they feel or sound hollow like a drum. Today is one of those days that even small terrain features could surprise you.

Avalanche Problem 2: Storm Slab
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WIth the high winds, storm slabs will only be found in areas sheltered by the wind. However, if you were to find an are the a storm slab exists, it could be really easy to trigger depending on the snow surface that it is sitting on. For example, if the snow from the past 24 hours is resting on windboard it will be easy to trigger due to the new snow having trouble bonding with that old hard surface. Play it safe for the next few days and ride in low angle terrain that is not under or connected to any steeper avalanche terrain.

Avalanche Problem 3: Loose Wet
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Rain fell on cold snow overnight in the lower elevations, and of course, that's never a good scenario. While this problem will be short-lived (due to the approaching cold front), until the snowpack can adjust, be aware of steep, lower elevation slopes and avoid terrain traps like gullies where damp snow can stack up deeply if a loose wet avalanche is triggered. 

advisory discussion

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recent observations

We have had a report of human triggered avalanches (wind slabs) from a group skiing terrain up Lick Creek on Saturday. Due to safe travel protocol, the skier was able to ski to a safe zone and no one was injured.

The storm front arrived yesterday to the West Central Mountains in the early afternoon, and it packed a punch. Winds were approaching 50 mph on West Mountain, and depending on your location, it dumped. Fortunately the temps stayed just low enough to allow for snow to the valley floor through the evening, until it turned to rain overnight. Throughout the day slopes on the north half of the compass loaded with any snow that would move, and made for some impressive wind affected snow and equally impressive wind slabs on northwest, north, northeast, and east aspects. 

 

weather

Mountain weather stations are currently reporting 28 to 36 degrees this morning. 1.9 inches of snow water equivalent (depending on temperatures, a rough estimate is for every inch of snow water equivalent we get 10 inches of snow) has fallen in the past 24 hours at Secesh Summit as of 4 am. Winds were out of the south and southwest blowing in the teen's to 20's overnight, with gusts blowing into the high 30's. Brundage Reservoir received 1.1 inches of snow water equivalent between 5 am yesterday and 10 pm last night (when station quite reporting).

For today expect the temperatures to slowly fall through the day with an approaching cold front. Weather models are showing another 0.5 inches of snow water equivalent by tonight, equating to another 4 to 10 inches of snow depending on location and how cool it has gotten when the precipitation falls (colder temperatures = lighter density snow = more snow). Another storm is on tap tonight into Tuesday into Wednesday. 

Due to the chance for significant snowfall the for the West Central Mountains, the National Weather Service out of Boise has issued a Winter Weather Advisory from tonight through Wednesday night for all upper elevations. 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Rain and snow showers, becoming all snow after 11am. Temperature falling to around 23 by 5pm. South southwest wind 8 to 14 mph. Chance of precipitation is 90%. Total daytime snow accumulation of less than one inch possible. Snow, mainly after 11pm. Low around 20. South wind 5 to 7 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches possible. Snow. High near 28. South southwest wind 7 to 11 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches possible.
Temperatures: Falling to 23 deg. F. Low 20 deg. F. High 28 deg. F.
Wind direction: South-southwest South South-southwest
Wind speed: 8 to 14 5 to 7 7 to 11
Expected snowfall: Less than 1 in. 1 to 3 in. 1 to 3 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Snow showers. Temperature falling to around 16 by 4pm. Wind chill values between -3 and 7. Windy, with a southwest wind 32 to 37 mph decreasing to 25 to 30 mph in the afternoon. Winds could gust as high as 49 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 2 to 4 inches possible. Snow, mainly after 11pm. Low around 15. Wind chill values between -4 and 1. Breezy, with a south southwest wind 21 to 26 mph decreasing to 15 to 20 mph in the evening. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible. Snow. High near 23. Breezy, with a west southwest wind 15 to 22 mph. Chance of precipitation is 90%. New snow accumulation of 2 to 4 inches possible.
Temperatures: Falling to 16 deg. F. Low 15 deg. F. High 23 deg. F.
Wind direction: Southwest South-southwest West-southwest
Wind speed: 32 to 37 decreasing to 25 to 30 21 to 26 15 to 22
Expected snowfall: 2 to 4 in. 2 to 4 in. 2 to 4 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Payette National Forest and the Friends of 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.