THIS SNOWPACK SUMMARY EXPIRED ON January 6, 2017 @ 10:15 pmSnowpack Summary published on January 6, 2017 @ 5:15 am
Issued by
Ben Bernall - Kootenai National Forest
Avalanche Character 1: Wind Slab
Wind Slab avalanches release naturally during wind events and can be triggered for up to a week after a wind event. They form in lee and cross-loaded terrain features. Avoid them by sticking to wind sheltered or wind scoured areas.
New Years Day brought a shot of new snow and northeast winds to the mountains of the Kootenai National Forest. These winds were enough to create wind slabs and cross-loading on exposed high elevation terrain. These slabs are becoming less reactive as time passes and the snowpack settles and strengthens.
Due to the northeast winds associated with the coldfront, backcountry users may find wind loading on aspects that don't align with our general wind patterns. This avalanche problem is primarily being found in the higher terrain with cross-loaded gullies, open ridgelines and steep, open slopes. Although we are finding this problem to be less reactive with time, it would be wise to assess steep open slopes very carefully before venturing out to play on them. Pay attention to changes in the snow density, shooting cracks and look for a pillow like appearance on the slopes.
Snowpack Discussion
On Thursday January 25th Nate and I traveled to Canuck Peak via the Spread Creek Road. After a rather brisk snowmobile ride we skinned up the southerly aspect of Canuck Peak. Pit results revealed very stable conditions within the snowpack. Our only failure in the extended column tests was approximately 12" below the surface. It failed on a layer of graupel with hard force (ECTN26). This layer of graupel was bonding well to the surrounding snowpack and did not produce a clean shear. Snowpack analysis in both the Purcell Range on Thursday and my ventures into the Eastern Cabinets on Monday the 2nd revealed very consistent results: good snowpack and stability test results with a windslab/crossloading hazard in higher exposed terrain.
On Sunday the weather appears to be making a change as the cold arctic air is pushed out and the "atmospheric river" and warmer air moves in. Keep an open mind as this weather change moves in on Sunday. Avalanche hazard generally increases with any sudden change in temperature or precipitation event.
recent observations
Click on the tabs to the left to submit any avalanche activity observations you may have from the Kootenai region and help keep your fellow backcountry travelers informed on conditions. Any additional info helps!
For those going across the border to ride in Idaho check out the conditions at:
http://www.idahopanhandleavalanche.org/current-advisory.html
Weather and CURRENT CONDITIONS
weather summary
Backcountry Forecast from NWS Missoula issued:
320 AM MST Fri Jan 6 2017
DISCUSSION: Cold temps and minor snow chances will persist for another 36 to
48 hours. Then milder air with a substantial subtropical moisture
push and increasing winds from the southwest develop late in the
weekend. This will result in low density snowfall transitioning to
higher density with more wind loading.
Kootenai:
--------------------------- 5000-7000 FT ----------------------------
Today Tonight Sat
Cloud Cover 80% 50% 60%
Hi/Lo Temps 10 to 15 -5 to 2 17 to 22
Winds(mph) SW 8 S 6 SE 5
Precip Chc 0 0 0
Precip Type sno/shr none none
Liquid Amt 0.00 0.00 0.00
Snow Ratio(SLR) 20:1 0 0
Snow Amt(in) 0 0 0
Snow Level 0 0 0
Disclaimer
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 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.
