THIS AVALANCHE ADVISORY EXPIRED ON March 16, 2019 @ 7:08 am
Avalanche Advisory published on March 15, 2019 @ 7:08 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Hazard is Moderate today.  The Sun will increase the hazard throughout the day and heat up the snow, along with a warming trend which may produce cornice failures, rollerballs and wet-loose slides on steep solar influenced slopes.  Wind slabs are a possibility in upper elevation exposed terrain.  Stay off sunny steep slopes that are receiving an excessive amount of heat. 

How to read the advisory


  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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Temperatures have been gradually rising each day, and are forecasted through the next week to be about 5-10 degrees above normal under clear sunny March skies. Each night, temperatures will dip back below freezing.  This melt-freeze cycle will stress and strengthen the snow pack. Wet-loose avalanches are possible. Stay off steep, really warm, solar effected slopes late in the day. Rollerballs and point releases, as well as an increase in boot, ski and or sled penetration depth in the snow are all indicators that the aspect is picking up too much heat, and you should choose a different, cooler aspect.

 

 

 

 

 

Avalanche Problem 2: Wind Slab
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Yesterday, before the winds died down, Northwest winds gusted upwards of 30 MPH pushing around about 4-6 inches of light snow creating shallow wind slabs that are sitting on crusts in places and may not be able to hold on under the weight of a skier or rider. 

Avalanche Problem 3: Cornice
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We have seen minimal cornice failure lately, but given the size of some of the cornices that are somehow still hanging on over the ridges, It's doubtful that they will survive the temperature swings that we are going to be seeing.  Stay far back from the edges of cornices as they may be stressed out, hanging over, and fail further back than you might expect. 

advisory discussion

PAC will issue 3 Advisories per week through the remainder of the winter as long as funding is available. 

Your Observations are extremely helpful and appreciated by all backcountry users.  If you have not checked our our Observations page, it is really easy to add snow or avalanche info.  Drop down menus and prompts will lead you through it and it is easy to add photos.

Please be aware that there are areas that are CLOSED to motorized traffic in the McCall, Goose Lake and greater West Mountains area.  Just because there are tracks in some areas, does not mean they are open.  Please respect all users and closures.  See the Payette Winter Travel Maps for clarification.  Both the East and West maps can be downloaded on the Avenza app on your phone or are available at trailheads and local shops.   IT IS YOUR RESPONSIBILITY TO KNOW WHERE YOU ARE AND WHERE THESE CLOSURES EXIST. 

recent observations

Yesterday, we ski toured the Snowslide Lake basin in the Lick Cr drainage East of McCall. The wind and Sun, along with a warming trend is consolidating our snow pack. Stability is improving, and we are definitely getting into spring conditions. Warming has been very gradual, and has produced minimal activity in the snow pack over the past couple days. A variety of crusts exist on solar aspects. Soft, cold powder is going to be hiding in High elevation wind and sun protected areas.

Skiers should definitely be carrying glop stopper, and other waxes to help slide in the warm afternoon snow. Scratchers on snowmobiles are going to be essential on groomed trails (especially early morning) , and if you have a big track you might want to carry spare scratchers in case you break them like we have lately?

 

 

 

 

 

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: 26 deg. F.
Average wind direction during the last 24 hours: N-S
Average wind speed during the last 24 hours: 3 mph
Maximum wind gust in the last 24 hours: 17 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

 

Area Forecast Discussion
National Weather Service Boise ID
347 AM MDT Fri Mar 15 2019

.SHORT TERM...Today through Monday...An upper level ridge will
build into the region over the short term. Expect quiet weather
and a warming trend, with temperatures rising to above normal by
Saturday and around 5 degrees above normal for Sunday and Monday.
Light winds expected.

.LONG TERM...Monday night through Friday...Upper ridge will
continue dry mild wx Monday night and Tuesday. Latest model
consensus shifts the ridge east of us Tuesday night allowing the
first of several Pacific short wave troughs to spread showers
northeastward into our CWA, mainly on the Oregon side. Another
trough will follow Wednesday night and Thursday. Short wave
ridging Thursday night and Friday morning will be followed by more
showers on the Oregon side later Friday, although the timing is
in doubt as models diverge around that time. We see no instability
for thunderstorms during the period.

&&

.AVIATION...VFR. Scattered middle and high clouds through 18Z then
mostly clear. Surface winds: variable less than 10 kts. Winds aloft
at 10k feet MSL: northwest 10-20 kts.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Mostly sunny, with a high near 38. Calm wind. Mostly clear, with a low around 19. Calm wind. Sunny, with a high near 41. Calm wind.
Temperatures: 38 deg. F. 19 deg. F. 41 deg. F.
Wind direction: Calm Calm Calm
Wind speed: 0 0 0
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Mostly sunny, with a high near 28. South southeast wind around 6 mph. Mostly clear, with a low around 22. Calm wind becoming southeast 5 to 9 mph after midnight. Sunny, with a high near 32. South southeast wind 5 to 7 mph becoming southwest in the afternoon.
Temperatures: 28 deg. F. 22 deg. F. 32 deg. F.
Wind direction: SSE SE SSE-SW
Wind speed: 6 5-9 5-7
Expected snowfall: 0 in. 0 in. 0 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.