THIS AVALANCHE ADVISORY EXPIRED ON February 15, 2020 @ 7:37 am
Avalanche Advisory published on February 14, 2020 @ 7:37 am
Issued by George Halcom - Payette Avalanche Center
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The Avalanche Hazard today is 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.

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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A little over a foot down from the snow surface, we have been finding some fragments of wind broken surface hoar buried 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, we have seen this layer producing failures in compression, but lacking the ability to propagate. 

Now, we are putting new snow on top of surface hoar that formed during this past weeks awesome clear nights. We will likely see some natural avalanches this weekend on this layer if we get the snow forecasted.  Buried surface hoar can be tricky, and when it propagates it can spread out fractures sometimes cross a whole ridgeline. We will be monitoring this problem closely over the next week.

Avalanche Problem 2: Wind Slab
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The winds have are forecasted to be around 10mph and out of the Southwest today and have gusted into th 30 mph range this morning. Older slab problems have likely bonded and strengthened, but you may find some small fresh, shallow wind slabs today.

advisory discussion

*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

On our ski tour yesterday, out North of Brundage Mountain Resort, we observed widespread Surface hoar sparkling in the Sun. We hope that this will not be a future problem?

We also noticed some Sun that was getting South aspects hot enough to melt the surface and likely forming crusts last night. (ESE aspect at around 7,000 feet.)

Our test pit showed a layer of buried surface hoar that we have seen elsewhere, about a foot down (under the lens the buried hoar was about 3-5mm and broken from the wind). Test results were moderate in compression, but lacked the ability to propigate on this North face of Sgt's, 7705 ft (CTM14SC, ECTN)

Below is a close up of the snow surface with a fresh crop of Surface Hoar!

 

 

 

 

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: 18 deg. F.
Max. temperature in the last 24 hours: 20 deg. F.
Average wind direction during the last 24 hours: NNE
Average wind speed during the last 24 hours: 16 mph
Maximum wind gust in the last 24 hours: 29 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

 

Area Forecast Discussion
National Weather Service Boise ID
301 AM MST Fri Feb 14 2020

.SHORT TERM...Today through Sunday night...Continued light snow
this morning along with pockets of gusty wind. Improving
conditions expected this evening ahead of the next approaching
system. The Saturday/Sunday system remains favored to be more
significant than the current system, with moderate to significant
amounts of mountain snow possible. As the moisture moves in
Saturday, snow levels will be at valley floors. However, as this
system progresses, snow levels will rise, leaving rain or a rain-
snow mix for most valley locations through most of the event.
Mountain snowfall, especially around the central Idaho mountains
looks to be 8 to 12 inches between Saturday and Sunday. Briefly
cooler temperatures expected on Saturday, with temperatures
warming to around 5 degrees above normal by Sunday.

.LONG TERM...Monday through Friday...Scattered snow showers will
begin to taper off Monday in the West Central and Boise mountains
and along the Nevada border as the low exits the region. High
pressure will build over the area Tuesday with dry conditions and
near normal temperatures for the rest of the period.

&&

.AVIATION...Generally VFR conditions at area terminals, with
periods of MVFR conditions at KMYL due to light snow. Mountain
obscurations expected with mountain snow continuing. Snowfall
should lessen after 00z this evening for a brief break in
activity. Surface winds are expected to be northwest around 10 kts
for the central mountains, with 10 to 15 kts possible for more
southern locations. Gusts of 25 to 30 kts could accompany some
wind today. Winds aloft at 10k feet MSL are expected to be west-
northwest at 35 to 50 kts.

Weekend Outlook...Precipitation expected Saturday afternoon
through Sunday, with MVFR to IFR conditions possible. Mountain
snow expected leading to continued mountain obscuration. Rain or a
rain-snow mix anticipated in the valleys with snow levels going
from 2500 to 3500 ft by late Saturday. Sunday evening will see a
return in valley snow as snow levels drop to valley floors.

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Snow likely, mainly after 11am. Partly sunny, with a high near 30. West southwest wind around 5 mph becoming calm. Chance of precipitation is 60%. Total daytime snow accumulation of less than a half inch possible. A 20 percent chance of snow after 11pm. Mostly cloudy, with a low around 20. Calm wind. Snow. High near 30. Calm wind becoming south southwest around 5 mph in the afternoon. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible.
Temperatures: 30 deg. F. 20 deg. F. 30 deg. F.
Wind direction: WSW Calm SSW
Wind speed: 5 becoming calm 0 5
Expected snowfall: 0 in. 0 in. 1-3 in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Snow. High near 18. West southwest wind 8 to 10 mph. Chance of precipitation is 80%. Total daytime snow accumulation of 1 to 2 inches possible. A 30 percent chance of snow after 11pm. Mostly cloudy, with a low around 12. South wind around 8 mph. New snow accumulation of less than a half inch possible. Snow. High near 20. South southwest wind around 9 mph. Chance of precipitation is 90%. New snow accumulation of 2 to 4 inches possible.
Temperatures: 18 deg. F. 12 deg. F. 20 deg. F.
Wind direction: WSW S SSW
Wind speed: 8-10 8 9
Expected snowfall: 1-2 in. less than one half 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.