THIS AVALANCHE ADVISORY EXPIRED ON February 16, 2020 @ 6:56 am
Avalanche Advisory published on February 15, 2020 @ 6:56 am
Issued by George Halcom - Payette Avalanche Center
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The Avalanche Hazard today remains Moderate above 7,000 feet on slopes that are wind loaded and steeper than 30 degrees. Below 7,000 feet the Avalanche Hazard is LOW. Buried surface hoar is preventing the upper 1-2 feet from bonding well, and may still produce human triggered avalanches. Over the next 24-48 hours we will see the avalanche hazard rise with more snow and wind.

How to read the advisory


  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Persistent Slab
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We have been finding some fragments of wind broken surface hoar, buried a little over a foot down from the snow surface, that was likely the culprit of a natural avalanche cycle that happened just towards the end of the last storm last weekend on North and East aspects. In out test pits throughout the advisory area this week, we have seen this layer producing moderate, broken failures in compression, and lacking the ability to propagate in extended column tests. 

Over the next 72 hours we will need to be cautious as we will be putting a new snow load on top of surface hoar that formed during this past weeks awesome clear nights. We may very well see some natural avalanches this weekend (Sunday-Monday) on this layer, and it may hang out and wait for a trigger like a snowmobile or skier in sheltered areas where the snow surface was protected from the Sun and wind this past week. 

Evaluate sheltered, steep slopes carefully this holiday weekend before committing to exposed, or big terrain. Buried surface hoar can be tricky, and when it propagates it can spread out fractures sometimes cross a whole ridgeline---we have to wait and see if this happens over the next 48 hours. Evaluate slopes carefully that are steep and protected, and definately spread out in steep terrain, use good safe travel protocols. We will be monitoring this problem closely over the next week.

Below is a photo of fresh Surface hoar at 7700 feet on a North aspect of Sgts Mountain Thursday afternoon.

Avalanche Problem 2: Wind Slab
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 Older slab problems have likely bonded and strengthened, but you may find some small fresh, shallow wind slabs today that formed yesterday from gusty northern winds. Above 7,000 feet is where you are most likely to find wind slabs, especially above 8,000 feet.  Watch out for red flags like cracks, or pillows, cornices, and wind scultpted snow. Idenifying theese features may be difficult today with fresh snow hiding the signs.

 

advisory discussion

Our annual fundraiser is this coming Friday, Februrary 21st at Banyons clubhouse on the McCall golf course. This year we will have a Silent Auction and Choose your own raffle prizes!  Live music by Jughandle Parade from 6-9!  Our goal this year is to raise $5000. which will go directly into additional forecasts for next season, our future forecasters scholarships and providing more Avalanche Awareness classes.  Tickets will be sold at the door.  $10.00 gets you in the doors with a raffle ticket.  Come on out and help make this years fundraiser this biggest yet!!

 

*Skiers and Snowmobiliers, the Granite Mountain closure went is in effect from January 15-March 31. Please respect Brundage Catski terrain closures which are CLEARLY marked on the west side of Goose Lake.  There is a shared use route at the northern end of the closure to allow access to Granite Mt Lookout and the upper east face of Granite Mt.  Additionally, public motorized use of ANY other Catski road is not permitted, including the roads between Brundage Reservoir and the East side of the Goose Lake Road in the Slab Butte and 76 areas. Please respect closed roads and areas and only ride on open roads and in open terrain.  There are also other areas that are closed to snowmobiling in the West Central Mountains. Click here for the Payette National Forest Winter Travel Map.

*Note to skiers accessing Jughandle Mountain from Silver Fox Trail.  Please park in signed areas only. Blocking or narrowing the road could result in loss of access to this area, ticketing or towing by Valley County.  There is NO parking allowed on the East side of the road or in the snowplow turnaround.  If you can't park in the signed area, park further down the road in a place where you are not obstructing traffi

recent observations

Yesterday, we ski toured just South West of Hard Creek Meadows, North of Brundage Ski Resort. We observed about an inch of new snow in the form of graupel, and had a variety of snow coming down, mostly in the form of 2-3 mm graupel. There was still a lot of soft snow to be had on aspects that did not receive direct Sun.

  Southern aspects had a 1 inch crust underneath the inch of graupel.

 

Our test pit at 7,000 feet on a Northwest aspect again revealed a layer of buried surface hoar about a foot down from the surface. The structure was right side up, and compression tests failed moderately (CT14Q2-Q3, SC), but lacked propagation in an extended column test (ECTN) .

 MIT Pit on the buried surface hoar. Moderate shear strength.

 

 

 

 

 

 

 

 

 

If you are out in the mountains and see recent avalanches, please take advantage of the good visibility and snap a picture to submit on our Observations page.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 14 deg. F.
Max. temperature in the last 24 hours: 19 deg. F.
Average wind direction during the last 24 hours: N
Average wind speed during the last 24 hours: 6 mph
Maximum wind gust in the last 24 hours: 18 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

Area Forecast Discussion
National Weather Service Boise ID
307 AM MST Sat Feb 15 2020

.SHORT TERM...Today through Tuesday...A North Pacific storm
will spread significant snow across Idaho north of the Snake
Basin late today through Sunday morning, and a winter weather
advisory remains in effect for it. Latest models have reduced
snowfall for Baker County and the advisory for that area has
been cancelled. Only an inch of snow is expected at lower
elevations in Baker County, with 1 to 3 inches in the mountains.
In the Snake Basin precipitation will start as wet snow late
this afternoon but change to rain by early evening. Rain will
continue tonight and Sunday morning with temperatures staying
above freezing all night. The storm`s cold front will pass
through Sunday morning and precipitation will quickly diminish.
Winds will shift to northwest or west and increase to 20 to 30
mph in the Snake Basin Sunday afternoon. Snow showers will
continue in the Idaho Mountains north of the Snake Basin then
taper off Sunday evening. A secondary surge of moisture will
come in from the north Monday and renew snow showers in the West
Central Idaho Mountains. The cold upper trough will settle over
our CWA Monday night, then shift east Tuesday morning placing
our area under cold, dry northerly flow aloft. Tuesday morning
will be quite cold, with sub-zero lows expected in the Camas
Prairie and other higher basins in Idaho. But Tuesday will also
be sunny and bright and afternoon temperatures will warm to normal.
Winds Tuesday will be light except in the central Snake Basin
where afternoon gusts to 20 mph are likely.

.LONG TERM...Tuesday night through Saturday...Models are in good
agreement that a broad ridge of high pressure will migrate over
the western US throughout much of next week. This will make for
seasonable and dry conditions. There are hints that the ridge will
break down and an active pattern will arrive by next weekend, but at
this point, confidence in the timing or intensity of that change is
quite low.

&&

.AVIATION...VFR overnight, with increasing clouds. Shower activity
will overspread the area from west to east today, with MVFR/IFR
possible over northern mountain areas after 16Z. Valley locations
should remain VFR, but occasional MVFR conditions are not out of
the question. Snow and clouds in the mountains will obscure terrain
from mid-morning through midday Sunday. Surface winds southwest to
southeast 5-15 kts. Winds aloft at 10k feet MSL west to northwest
35 to 50 kts. Snow levels rising to 4000-4500 feet MSL after 16/00z.

Sunday Outlook...Precipitation in northern areas with widespread
mountain obscuration and areas of MVFR and local IFR conditions
continuing through at least midday Sunday.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory from 11 AM this morning to 11 AM MST
Sunday IDZ011-033.
Winter Weather Advisory from 5 PM this afternoon to 11 AM MST
Sunday IDZ013.
OR...None.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Saturday Saturday Night Sunday
Weather: Snow. High near 30. Calm wind becoming south southwest around 5 mph in the afternoon. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 3 inches possible. Snow. Low around 29. Light south wind. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible. Snow likely before noon, then snow showers likely after noon. Mostly cloudy, with a high near 33. Light south southwest wind becoming west 6 to 11 mph in the afternoon. Chance of precipitation is 70%. New snow accumulation of 1 to 3 inches possible.
Temperatures: 30 deg. F. 29 deg. F. 33 deg. F.
Wind direction: SSW S SW-W
Wind speed: 5 Light 6-11
Expected snowfall: 1-3 in. 3-5 in. 1-3 in.
Granite Mountain at 7700 feet.
  Saturday Saturday Night Sunday
Weather: Snow. High near 20. South southwest wind around 9 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 3 to 5 inches possible. Snow. Low around 17. South southwest wind around 11 mph. Chance of precipitation is 100%. New snow accumulation of 4 to 8 inches possible. Snow likely before 11am, then snow showers after 11am. High near 21. West wind 10 to 15 mph. Chance of precipitation is 80%. New snow accumulation of 2 to 4 inches possible.
Temperatures: 20 deg. F. 17 deg. F. 21 deg. F.
Wind direction: SSW SSW W
Wind speed: 9 11 10-15
Expected snowfall: 3-5 in. 4-8 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.