THIS AVALANCHE ADVISORY EXPIRED ON February 1, 2020 @ 5:32 amAvalanche Advisory published on January 31, 2020 @ 5:32 am
Issued by
Ben Bernall - Kootenai National Forest
Kootenai

bottom line
Warm temperatures and rain up to 7,500' are being forecast for Friday afternoon. Anticipate avalanche danger to rise on Friday at all elevations. Avoid avalanches by avoiding be on or below steep terrain on Friday and Saturday. Natural avalanches may be possible and human triggered avalanches are likely on Friday.
Kootenai
How to read the advisory
Warm temperatures and rain up to 7,500' are being forecast for Friday afternoon. Anticipate avalanche danger to rise on Friday at all elevations. Avoid avalanches by avoiding be on or below steep terrain on Friday and Saturday. Natural avalanches may be possible and human triggered avalanches are likely on Friday.

3. Considerable
?
Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
3. Considerable
?
Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
3. Considerable
?
Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wet Slab
-
Type ?
-
Aspect/Elevation ?
-
Likelihood ?CertainVery LikelyLikelyPossibleUnlikely
-
Size ?HistoricVery LargeLargeSmall
Warm temperatures and .6 inches of water will fall on the existing snowpack Friday afternoon and cause the upper 18-24" of the snowpack to become wet, heavy and weak up to 7,500' in elevation. Natural avalanches will be possible and they have potential to run to drainage bottoms if they release in large start zones at upper elevations. This problem will be a concern until Saturday afternoon when a cold front is forecast to enter the area and lower the snowline. Avoid being on or below steep terrain while these warm, rainy conditions are present.
Avalanche Problem 2: Wind Slab
-
Type ?
-
Aspect/Elevation ?
-
Likelihood ?CertainVery LikelyLikelyPossibleUnlikely
-
Size ?HistoricVery LargeLargeSmall
On Thursday wind slabs were our primary concern as we noted very obvious effects of southwest winds that blew across the area early this week. They were less reactive; but, still a concern. On Friday and Saturday this problem will remain a hazard as the warm temperatures and rain will stress these slabs and cornices on north and east facing terrain. On Saturday the snowline will drop and the winds will continue and raise the hazard of wind slabs above 6,000'.
Avalanche Problem 3: Loose Wet
-
Type ?
-
Aspect/Elevation ?
-
Likelihood ?CertainVery LikelyLikelyPossibleUnlikely
-
Size ?HistoricVery LargeLargeSmall
It's gonna get sloppy out there on Friday afternoon!! Expect to see "loose-wet" slides flow freely down the hill up to 7,500' in elevation. By Saturday this problem will mainly be a concern at Treeline and below as the temperature drops and the rain turns back to snow at upper elevations. These slides are often slow and harmless in appearance. If you find yourself in trees or cliffs they will hurt you. Give this problem some respect in steep terrain with trees and cliffs.
advisory discussion
We have a dynamic situation right now in regards to weather and avalanche hazard. Yesterday we observed a very stable and cohesive snowpack. Our primary concern was windslab on north and east facing terrain where the southwesterly winds have built large cornices and cohesive wind-slabs. There are a couple of weak layers in the upper snowpack but neither were showing a high likelihood of failing. We will see a big change by Friday afternoon with the incoming weather. Temperatures are starting to climb and mountain rain is on the way. Discussions this morning with the National Weather Service indicate that by Friday afternoon it will be raining to at least 7,500' or higher. This will cause our upper snowpack to become heavy and weak. I anticipate that we will initially see lots of loose-wet avalanche activity early on followed by the potential for slabs to release in the upper 18-24" of the snowpack.
By Saturday morning the rain/snow-line is expected to drop back down to 6,000' and strong winds out of the southwest will hammer the area. With this you can anticipate the problems above treeline to shift back to a storm slab and wind slab concern. At lower elevations below 6,000' expect "loose-wet" and "wet-slabs" to remain the primary concern until Saturday afternoon.
Weather and CURRENT CONDITIONS
weather summary
Backcountry Forecast from NWS Missoula issued: 400 AM MST Fri Jan 31 2020 DISCUSSION: Northwest Montana: Light to moderate snow will continue for all elevations through the early morning hours. By late morning, into the afternoon, warmer air aloft will move into the region changing snow to a rain/snow mix for elevations of around 5000 feet and below. Above that, all snow is expected to continue through the rest of the daylight hours. Strong gusty westerly winds are expected today as well, above 5000 feet. Wind gusts could be approaching 50 mph by early afternoon. Even stronger winds will be moving through northwestern Montana for most of the day Saturday. Gusty westerly winds in the Mission and Swan Ranges, as well as GNP and the Bob Marshalls, will be exceeding 65 mph by the afternoon. A strong cold front will move through the area by sunset, bringing heavy snow and continued strong winds to the higher terrain.
Kootenai: --------------------------- 5000-7000 FT ---------------------------- Today Tonight Sat Cloud Cover 90% 75% 90% Hi/Lo Temps 35 to 40 29 to 36 34 to 40 Winds(mph) SW 25G55 SW 36G64 SW 43G78 Precip Chc 90 70 90 Precip Type sno/rain sno/rain sno/rain Liquid Amt 0.57 0.15 0.45 Snow Ratio(SLR) 11:1 8:1 13:1 Snow Amt(in) 1-6 0-2 5-7 Snow Level 6000 6500 5000
Disclaimer
Avalanche conditions change for better or worse continually. Backcountry travelers should be prepared to assess current conditions for themselves, plan their routes of travel accordingly, and never travel alone. Backcountry travelers can reduce their exposure to avalanche hazards by utilizing timbered trails and ridge routes and by avoiding open and exposed terrain with slope angles of 30 degrees or more. Backcountry travelers should carry the necessary avalanche rescue equipment such as a shovel, avalanche probe or probe ski poles, a rescue beacon and a well-equipped first aid kit. For a recorded version of the Avalanche Advisory call (208)765-7323.
This website is owned and maintained by the Friends of the Idaho Panhandle Avalanche Center. Some of the content is updated by the USDA avalanche forecasters including the forecasts and some observational data. The USDA is not responsible for any advertising, fund-raising events/information, or sponsorship information, or other content not related to the forecasts and the data pertaining to the forecasts.