THIS AVALANCHE ADVISORY EXPIRED ON December 18, 2015 @ 6:27 am
Avalanche Advisory published on December 17, 2015 @ 6:27 am
Issued by -
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Starting out today the Avalanche Hazard is MODERATE in the PAC Advisory Area. An incoming Pacific Storm and an associated Winter Storm Warning will bring heavy snowfall to the West Central Mountains today and into tonight. As this storm takes hold on the PAC Advisory Area expect the Avalanche Danger to rise to CONSIDERABLE in the highest of elevations where the combination of south-southeast winds combined with heavy snowfall could make travel in avalanche terrain quite dangerous.

How to read the advisory


  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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With winds coming from most all directions over the last week and a half, wind slabs are not favoring one aspect over another in the higher elevations. Triggering a wind slab is still possible in these high evlevations and careful route finding and line choice will be the key to not awakening these sleeping slabs. If a wind slab was triggered it could step down causing a larger avalanche. 

Tonight into tomorrow expect strong winds out of the south-southwest. These winds combined with new snowfall are going to cause for sensitive wind slabs on all Leeward slopes.

 

Avalanche Problem 2: Storm Slab
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A Winter Storm Warning is in effect due to a Pacific Storm that could dump up to 2 feet of snow on our PAC advisory area in the next 24-36 hours. If this forecast comes true you can expect to trigger strom slabs on slopes over 30 degrees. Remember with Storm Slabs you do not need to be in big terrain for these to prove deadly. Terrain choice and avoidance of Terrain Traps is going to be important as the snow piles up.

advisory discussion

This next storm, combined with increase ability to travel in the high country, is going to cause for dangerous avalanche conditions this weekend in the PAC Advisory Area. Please use caution and follow good travel protocols..Beacon, shovel, probe for every person in your group. Travel one at a time when travelling across a slope that could avalanche( even in small terrain such as gullies and 'road cuts'. 

recent observations

While out in the Advisory Area yesterday no Red Flags were observed: No whoomping (collapse of a weak layer), no cracking, and no recent avalanches...

10-20 inch slabs were found while out riding off of Warren Wagon Road. These slabs were unsolidated but yet reactive. This could change today as new warmer/ heavier snow falls onto yesterdays light/low density powder, which in turn could cause this loose unconsolidated snow to become reactive to the heavy load.

weather

There was 1-4 inches of new snow in the last 24 hours in and around McCall with temperatrues in the single digits in the high country overnight. But light flurries and cold temps are not going to be the norm over the next few days, this is because yet another Pacific Storm is knocking at our door! A WINTER STORM WARNING is in effect begining this morning at 11 AM and will last until Friday morning at 11AM. This means that heavy snowfall will impact the West Central Mountains later today through Friday. The snow will come with an increase in temperature due to it being pushed into the area by a warm front. Expect to see the snow start around 9 AM and produce 4-6 inches by the time the sun sets this afternoon and drop another 12-16 inches overnight. If snow is what you wanted for the Holidays, the PAC Advisory area is where you want to be this weekend!

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Thursday Thursday Night Friday
Weather: Snow, mainly after 11am. High near 23. East wind 5 to 11 mph becoming south in the morning. Chance of precipitation is 100%. New snow accumulation of 2 to 4 inches possible. Snow. Temperature rising to around 32 by 4am. South wind 9 to 13 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 7 inches possible. Snow before 11am, then rain and snow. High near 34. South wind 11 to 13 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible.
Temperatures: High 23 deg. F. Rising to around 32 deg. F. High 34 deg. F.
Wind direction: East becoming south South South
Wind speed: 5-11 9-13 11-13
Expected snowfall: 2-4 in. 3-7 in. 3-5 in.
Granite Mountain at 7700 feet.
  Thursday Thursday Night Friday
Weather: Snow, mainly after 11am. High near 24. Breezy, with a west northwest wind 7 to 12 mph becoming southwest 18 to 23 mph in the afternoon. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible. Snow. Temperature rising to around 30 by 10pm. Breezy, with a west southwest wind 20 to 28 mph, with gusts as high as 37 mph. Chance of precipitation is 100%. New snow accumulation of 4 to 8 inches possible. Snow. High near 29. Windy, with a southwest wind 28 to 36 mph, with gusts as high as 46 mph. Chance of precipitation is 100%. New snow accumulation of 5 to 9 inches possible.
Temperatures: High 24 deg. F. Rising to 30 deg. F. High 29 deg. F.
Wind direction: Becoming southwest West-southwest Southwest
Wind speed: 18-23 in afternoon 20-28 gusts to 37 28-36 gusts up to 46
Expected snowfall: 3-5 in. 4-8 in. 5-9 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.