Avalanche Advisory published on March 30, 2018 @ 6:47 am
Issued by Dave Bingaman - Payette Avalanche Center
bottom line

The Avalanche Hazard is Low today.  The potential for small loose/wet avalanches and failing cornices will increase later in the day as temperatures warm.  Steep, rocky slopes on the southern half of the compass will have the highest potential for wet slides.  Indicators of increasing instability include: roller balls and cinnamon rolls or a change from a supportable crust to  an unsupportable one.  If you notice these signs, it is time to move to a cooler slope.

How to read the advisory

  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Loose Wet
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Small loose, wet avalanches may occur as the sun and air temperature warm the upper snowpack today.  This type of avalanche is most likely on steep, upper or mid elevation rocky slopes that are getting direct sunlight in addition to the  above freezing mid day temperatures.   By mid afternoon yesterday, the corn and underlying supportable crust was just turning into a sticky, bottomless mess.  If you notice this occurring, it is time to call it a day or move to a cooler, shadier aspect. 

In addition to small loose/wet slides today, cornices are a growing concern.  There are still plenty of large, overhanging cornices that are going to begin to fail as we see more warm weather through the rest of the spring.  Give overhanging cornices a wide berth especially later in the day as temps climb. Avoid travel on big cornices or directly below them.

advisory discussion

Tomorrow, March 31 will be our last advisory of the season unless we see a major change in conditions.  Thank you to all of our volunteer travel companions for joining us on good days and not so good days.  Also, a big thanks to Brian Peters for organizing the Friends fundraiser this year almost single handedly!  Thanks to all of the merchants and companies that donated to the fundraiser.  Finally, thank you to all of the folks that sent us observations or snow reports from across the advisory area throughout the winter.  If you would like to get involved with the Friends, please contact Susan Jenkins at the McCall Ranger District: 208-634-0400.

Also, Tamarack Resort is hosting it's first ever Snowmobile Hillclimb competition which is being put on by RMSHA on April 7 and 8.  Don't miss out on a chance to get close to the action and see some great riders at a local venue.  Click here for more info.


recent observations

We toured to the north and south of Tamarack Resort yesterday to take advantage of the superb corn skiing and fast travel conditions on the West Mountain Crest yesterday.  The snowpack is incredibly stable with the recent melt/freeze cycle that we have seen over the last week.  Last week's rain and warmup did a great job smoothing out and giving the snowpack a uniform surface.  We saw signs of instability from that rapid warmup last week but no recent signs of instability.  The crust is supportable and the underlying snow was cohesive  down to the old crust from the last melt/freeze cycle.  We were able to push a little bit of the surface snow off later in the day as the crust began to soften but the crust stayed firm until the late afternoon.  These mostly stable conditions should remain until we see a significant change in either temperature or precipitation.

Here are a few pics from the area between the resort and Poison Creek from yesterday.  The old crown and large cornice failure occurred last week, probably as a result of the rain event which reached all the way to the top of the West Mountain crest. The large cornice is on the East side of Lone Tree and is approximately 12-15 feet tall.




CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 26 deg. F.
Max. temperature in the last 24 hours: 30 deg. F.
Average wind direction during the last 24 hours: W
Average wind speed during the last 24 hours: 7 mph
Maximum wind gust in the last 24 hours: 16 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 59 inches

SHORT TERM...Today through Saturday...Pattern remains similar to
past shifts, with a northwest flow over the area. Weak amounts of
moisture remain embedded in the flow, and may produce a few
mountain showers this afternoon, mainly across the West Central
Mountains of Idaho. Expect another round of gusty wind across the
Western Magic Valley this afternoon, which should weaken during
the early evening hours. Temperatures will continue to warm today
with values around 5 to 10 degrees above normal. The pattern will
then shift tonight as a cold front moves through the area. Models
continue to show a band of shower activity spread from Baker
County of Oregon east through the Boise Mountains for Saturday
morning and afternoon. Increased probabilities for these showers
as models have been a bit more consistent in its development.
Shower activity will then shift north on Saturday afternoon, with
activity anticipated across the central mountains of both Oregon
and Idaho. Temperatures will cool on Saturday in response to this
system, though will still be right around or just above normal

.LONG TERM...Saturday night through Thursday...Northwesterly flow
aloft will continue to bring periods of cloudiness across the
northern half of the forecast area with mostly clear skies across
the southern portion through Sunday. A cold front will pass
through the area on Monday bringing a chance snow showers to the
mountains above 5500 feet and a chance of rain showers to valley
locations. Windy conditions are expected to develop behind the
front on Monday afternoon especially for areas east of Mountain
Home...including the Magic Valley. Tuesday is looking mostly dry
across the area with lighter winds. The chance of precipitation
increases again by Wednesday and it looks like it will be pretty
wet across southwestern Idaho and southeastern Oregon towards the
end of the week.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Mostly cloudy, with a high near 49. Light and variable wind becoming southwest 5 to 9 mph in the morning. Mostly cloudy, with a low around 28. West southwest wind 5 to 8 mph becoming calm in the evening. A 20 percent chance of showers after noon. Mostly cloudy, with a high near 48. Calm wind becoming southwest 5 to 7 mph in the afternoon.
Temperatures: 49 deg. F. 28 deg. F. 48 deg. F.
Wind direction: SW SW SW
Wind speed: 5-9 5-8 5-7
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Mostly cloudy, with a high near 35. Southwest wind 11 to 14 mph. Mostly cloudy, with a low around 24. West wind 5 to 13 mph. A 20 percent chance of snow showers after noon. Mostly cloudy, with a high near 33. Calm wind becoming west southwest 5 to 7 mph in the afternoon.
Temperatures: 35 deg. F. 24 deg. F. 33 deg. F.
Wind direction: SW W SW
Wind speed: 11-14 5-13 5-7
Expected snowfall: 0 in. 0 in. 0 in.

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.