THIS SNOWPACK SUMMARY EXPIRED ON December 17, 2017 @ 5:15 amSnowpack Summary published on December 15, 2017 @ 5:15 am
Issued by Ben Bernall - Kootenai National Forest
The good news is that we are in a period of LOW avalanche danger and our snowpack is currently very stable. The bad news: We have a solid rain crust with a layer of facets (weak, sugary snow) and widespread surface hoar crystals growing on the snowpack. If and when we get more snow we can expect a drastic decline in snowpack stability.
Avalanche Character 1: Loose Dry
Loose Dry avalanches exist throughout the terrain, release at or below the trigger point, and can run in densely-treed areas. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells.
The upper 6-8" of the snowpack consists of poorly consolidated snow that is not bonded to the Thanksgiving rain crust. In steep terrain this loose snow could knock a skier or rider off balance. Though these sloughs are unlikely to bury you they could cause injury in high consequence terrain if trees and rocks are in your path of descent.
On December 14th we travelled into the Keeler Rattle area where we found very stable snow conditions and some very impressive surface hoar development. Snowpit stability tests revealed a stout rain crust at the bottom 2' of the snowpack, overlying this was a thin layer of facets covered by another layer of light powder. We observed surface hoar as high as 6,000' in elevation on all aspects although it was much smaller and broken down in areas with a little exposure to wind and sun. In some areas the crystals were up to 1.5" long. Between the facet layer and this widespread surface hoar we will have alot of potential instabilities in the snowpack when snowy weather returns.
It's pretty on the surface! But deadly when its buried.
Weather and CURRENT CONDITIONS
Backcountry Forecast from NWS Missoula issued: 500 AM MST Fri Dec 15 2017 DISCUSSION: A weak winter storm cycle will exist over the region for at least the next week beginning Friday afternoon. Snow levels will be just above valley elevations for much of the first system, with up to 8 inches total accumulation at pass elevations today through Saturday. Wind gusts over 40 mph along the Continental Divide will make backcountry travel difficult through tonight. Winds lighten up by Saturday midday. The following storm system on Sunday- Monday will have similar snow and wind concerns along Continental Divide as well. A much colder pattern will arrive for the latter half of next week, however no significant breaks between mountain snows anticipated. Kootenai: --------------------------- 5000-7000 FT ---------------------------- Today Tonight Sat Cloud Cover 90% 90% 75% Hi/Lo Temps 26 to 31 17 to 21 21 to 28 Winds(mph) SW 15G32 W 6G18 W 5 Precip Chc 100 60 30 Precip Type snow snow sno/shr Liquid Amt 0.12 0.10 0.01 Snow Ratio(SLR) 13:1 17:1 18:1 Snow Amt(in) 1-2 1-3 0 Snow Level 1500 1500 1000
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.