THIS AVALANCHE ADVISORY EXPIRED ON February 21, 2017 @ 6:45 am
Avalanche Advisory published on February 20, 2017 @ 6:45 am
Issued by Kent May - Payette Avalanche Center
bottom line

The avalanche danger is CONSIDERABLE above 7,000 feet. Snow and strong wind have created slabs in exposed and sheltered terrain on multiple aspects. Multiple generations of wind slabs will be sensitive to the weight of riders, may be up to 2’ thick, and have formed over a variety of surfaces.  Wind slabs are less widespread at middle and low elevations where MODERATE danger exists. In the lowest elevations there is a possibility of wet avalanches due to forecasted rain today. 

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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With another windy day in the upper elevations wind slabs are our number one concern. Depending on location, you can find a few different generations of wind slabs that have developed over the last few days. The most suspect slopes today will be the ones with any north facing tilt due to the wind being primarily out of the south throughout this storm and again today. However, yesterday I saw wind loading and slab development on east aspects as well. As usual with wind, it is variable and be on the lookout for clues of wind loading on all slope in the upper elevations. 

Winds from Granite Moutain weather station below. Notice gusts mid day yesterday.

Avalanche Problem 2: Storm Slab
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Over the last 24 hours we have gotten 2 to 10 inches of snow and today we will see another 3 to 10 inches of snow depending on location and elevations. Totals around the advisory area are nearing 20 inches over the last 48 hours. In areas that were sheltered from the wind expect to find storm slabs again today. These storm slabs will be quite tender and easy to trigger, especially on steep slopes. The bond is getting better between saturday's snow and the crust below, however, the interface between the different storm layers has now become our primary concern with the storm slab problem.

Play it safe today and stick to low angle slopes and meadows and enjoy the powder.

advisory discussion

Snowmobiler/Snowbiker Travel Restrictions: Granite Mountain Area Closure is in effect Jan15-March 15, please respect Snowcats operating in this and nearby areas.  In addition there are other areas on the Payette National Forest that are CLOSED to snowmobile traffic including Jughandle Mt east of Jug Meadows,North of Boulder Mtn, East of Rapid Peak,  Lick Creek/Lake Fork Drainage (on the right side of the road as you are traveling up canyon), and the area north of Brundage Mt Ski area to junction "V" and along the east side of Brundage and Sergeants' Mts. with the exception of the Lookout Rd( junction "S").

 Please respect these closures and other users recreating in them.  Winter Travel Map(East side). You can download the map to the AVENZA app on your phone, and know your exact location while you are out riding.  It is your responsiblity to know where closures exist on the forest.

The Friends of the Payette Avalanche Center (FPAC) needs YOU! We are in desperate need of more user support and financial assistance. The avalanche forecast is not a guaranteed service, and is in jeopardy of dwindling down to only a couple of days a week in the near future. Please help if you can by clicking the DONATE tab above. If you value this life saving information, make a donation or help the FPAC in raising funds for the future.

We rely on our snowmobiles to bring you quality forecasts. Currently two of our sleds have nearly 8,000 miles on them. We need your help raising funds for replacements! Please contact us if you can help in any way.

recent observations

We had a report from local guides yesterday of natural storm slab avalanches on northwest aspects at around 7,000 feet on Double North. These naturals were failing on 38 degree slopes and ran 150 feet with a crown of appox. 1 foot. On Slab Butte these same guides were able to get slabs to release 10-12 inches deep on steep roll overs with ski cuts on west aspects.

In the southern portion of the advisory area Tamarack Ski Patrol reported very small avalanche activity during morning avalanche mitigation. However, later in the day, wind slabs began to develop on northeast facing terrain due to winds out of the southwest.

*IF YOU GET OUT TODAY, PLEASE LET US KNOW WHAT YOU SEE! 

forecast@payetteavalanche.org

Or use the OBSERVATION tab at the top of this advisory.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 25 deg. F.
Max. temperature in the last 24 hours: 25 deg. F.
Average wind direction during the last 24 hours: soutwest
Average wind speed during the last 24 hours: 4 mph
Maximum wind gust in the last 24 hours: 33 mph
New snowfall in the last 24 hours: ~3 inches
Total snow depth: NA inches
weather

Today snow showers. Some thunder is also possible. High near 32. Windy, with a south wind 22 to 30 mph, with gusts as high as 41 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 3 to 7 inches possible.

LONG TERM...Tuesday night through Sunday...Southwest flow aloft Tuesday night with a deepening trough offshore will keep precipitation going across the the region through Wednesday morning. Pattern transitions to a large trough over the Western conus with a large ridge over the Eastern Pacific. This will bring colder-than- normal temperatures into the weekend. Snow levels start Wednesday around 4000 feet MSL, but quickly drop to valley floors by Wednesday afternoon. Weak upper level troughs pass over the region Thursday through Monday and bring a chance for snow showers each day. The showers will be, for the most part, convectively driven favoring the afternoons and early evening time periods. Temperatures will climb above freezing during the daytime, and with ground temperatures above freezing at most lower valley locations (except for the Lower Treasure Valley), impactful accumulations are not expected in the valley. Temperatures stay below normal during the period with the coldest day being Friday.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Snow showers before 11am, then rain showers. Some thunder is also possible. High near 39. South wind 11 to 16 mph. Chance of precipitation is 100%. Total daytime snow accumulation of around an inch possible. Rain showers likely before 11pm, then rain and snow showers. Low around 33. South wind around 11 mph. Chance of precipitation is 100%. Little or no snow accumulation expected. Rain and snow showers, becoming all snow after 11am. Some thunder is also possible. High near 38. Breezy, with a south southwest wind 18 to 22 mph. Chance of precipitation is 90%. New snow accumulation of less than a half inch possible.
Temperatures: high 39 deg. F. low 33 deg. F. high 38 deg. F.
Wind direction: south south south-southwest
Wind speed: 11-16 11 18-22
Expected snowfall: 1 in. little to none in. Less than .5 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Snow showers. Some thunder is also possible. High near 32. Windy, with a south wind 22 to 30 mph, with gusts as high as 41 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 3 to 7 inches possible. Snow showers. Low around 24. Breezy, with a south southwest wind 20 to 26 mph, with gusts as high as 36 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible. Snow showers. High near 32. Windy, with a south southwest wind 29 to 32 mph, with gusts as high as 44 mph. Chance of precipitation is 100%. New snow accumulation of 5 to 9 inches possible.
Temperatures: high 32 deg. F. low 24 deg. F. high 32 deg. F.
Wind direction: south south-southwest south-southwest
Wind speed: 22-30 gusting 41 20-26 gusting 36 29-32 gusting 44
Expected snowfall: 3-7 in. 3-5 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.