Our snow pack is going to be problematic for stability for some time, especially with added load from over a foot of snow with South winds upwards of 20 MPH forecasted over the next few days. The temperatures associated with the forecasted storm are warm, and will likely form an upside down layer.
Right now, we have a stereotypical, fairly poor, and complex snow pack with multiple weak layers. The old October snow and early November snow that is the foundation of our snow pack has turned into Depth Hoar, a sugary junk pile near the ground with 2 additional weak layers above including buried surface hoar and Near Surface Facets. Avoid steep slopes especially on protected northerly slopes that have poor structure and will be getting the most load from South wind loading. Our next update will be out on Friday, Dec 20th. Stay safe out there.
|0600 temperature:||21 deg. F.|
|Max. temperature in the last 24 hours:||21 deg. F.|
|Average wind direction during the last 24 hours:||SE|
|Average wind speed during the last 24 hours:||9 mph|
|Maximum wind gust in the last 24 hours:||21 mph|
|New snowfall in the last 24 hours:||0 inches|
|Total snow depth:||NA inches|
Area Forecast Discussion
National Weather Service Boise ID
407 AM MST Wed Dec 18 2019
.SHORT TERM...Today through Saturday...Dry weather continues today
as an upper ridge over the region shifts eastward. Snow will
develop from west to east overnight as moist westerly flow pushes
into the Pacific Northwest. Southeast Oregon and the west-central
Idaho mountains will see snow begin overnight, before filling in
across the lower Snake Plain by sunrise Thursday. The heaviest
snowfall for this event will be focused across the mountains of
Baker county and west-central Idaho. The Lower Treasure Valley
will see light accumulations Thursday morning, likely initiating
around rush hour, and with temperatures at or below freezing,
expect potential for slick roads. Snow levels will rise from
lowest valley floors to around 4k feet by Thursday afternoon.
Morning snow accumulations will likely melt off during the
afternoon across lower elevation as temperatures warm above
freezing. Open terrain and higher mountains will see breezy
conditions through this event. The precipitation shifts northward
overnight as the flow aloft backs around to the southwest. This
will confine snowfall to the central Idaho mountains Thursday
night into Friday. Conditions dry out for most sites late Friday
and into Saturday as a trough deepens offshore, keeping the area
under southwest flow. Temperatures are near normal through
Thursday warming to around 10 degrees above normal for Friday and
.LONG TERM...Saturday night through Tuesday...A trough along the
west coast will slowly track eastward during the weekend and into
next week, supporting a chance of showers over the area each day.
The best chance for showers will be over southeast Oregon and the
mountains of southwest Idaho. Snow levels will begin around
3500-4500 feet MSL, and gradually lower to valley floors by
Monday/Tuesday. Temperatures will be on a cooling trend, but still
around 5-10 degrees above normal through the extended.
.AVIATION...Mainly VFR with mid to high clouds. Patchy fog
creating IFR/LIFR at KMYL through morning. Low clouds and mountain
obscurations by this evening. Isolated snow showers will begin
over SE Oregon by 00z/Thu, and spread into SW Idaho after 03z/Thu.
Then, expect widespread snow after 12z/Thu. Surface winds: SE to
SW 5-15 kts, except NE 20-30 kts at KJER. Winds aloft at 10Kft
MSL: W to SW 20-35 kts.
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.