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07/01/26_advisory
INTRODUCTION:
This is Tony
Willits with the backcountry avalanche advisory issued by
the U.S. Forest Service Glacier Country Avalanche Center at 7:00 AM,
Friday, April 11th for the Glacier Park and Flathead and Kootenai
National Forest areas.�
HAZARD ANALYSIS
Between 5000' and 7000' of elevation we are rating the avalanche danger
as MODERATE.
Below
5000 feet of elevation the avalanche danger is
currently being rated as LOW.
These danger
ratings expire at midnight, Friday, April 11th.�
The avalanche danger will likely escalate especially on south and west
aspects with the warming that is expected this weekend.
Because of the
general nature of this advisory message, each
backcountry party will always need to make their own time and site
specific avalanche hazard evaluations.
� �
� ��
SNOWPACK
ANALYSIS:
Our backcountry
observations Thursday were from Jewel Basin on the Flathead
National Forest and from Whoopee-Hiatt Divide in the West
Cabinets on the Kootenai National Forest.
In the past 24 to 48 hours, storm/squall accumulations have been more
on the moderate side in the Missions and Swan Ranges while elsewhere in
the advisory area light to nil.� The cloudy, squally weather
pattern has maintained soft surface layers quite well for this late
season date.� Surface layers from 30 to 40 cms down, were the
location of the weak interfaces but none were revealing clean or crisp
shears. �� Wind transport was apparent at ridge tops at least
in the Swan Range.� �
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��� �� �� ��
AVALANCHE -
INSTABILITY DESCRIPTION:
Between 5000 and
7000 feet
of
elevation, the avalanche danger
is currently being
rated as MODERATE� unstable
slab layers are possible�on steep
terrain. Natural avalanches are unlikely, while human triggered
avalanches are possible. Backcountry travelers should use caution in
steeper terrain on certain aspects.
Below 5000 feet of
elevation the avalanche danger is currently being rated as�
LOW, snow is generally stable with only isolated areas of
instability. Natural avalanches are very unlikely, while human
triggered avalanches are unlikely. Backcountry travel is generally
safe. Normal caution is advised.��
WEATHER
FORECAST & AVALANCHE OUTLOOK:
`
Current Western Montana NWS Backcountry Weather Forecast
�
An upper jet ahead of a building upper ridge will keep showers over the
Inter Mountain West through Friday morning.� The jet will move off
to the east as the ridge builds east Friday evening.� Warming
under mainly clear skies will be the weather story for the weekend.
�
Traveling over
steep open terrain will require normal precautionary measures, although
the risk will rise associated with significant warming and thawing this
weekend.� South and west aspects will react with the expected thaw
and will be locations to avoid as temperatures climb during the day.
� Surface sluffs and roller ball activity could cause slopes to
pull down into deeper buried weak interfaces creating natural avalanche
activity.� Cornice failures over the next few days could at least
test the shaded aspects if temperatures climb as expected. �
Please
note
that this avalanche advisory is our best interpretation of
snowpack conditions and National Weather Service forecasts on the day
the advisory is issued. Unanticipated weather changes such as wind, a
marked temperature increase, or precipitation beyond forecast amounts
can increase the avalanche danger. Local variations may also exist.
This is the
last regular Glacier
Country Avalanche Advisory for the 2007-2008 winter season.� Special
Advisories will be posted as per normal operations that an aggressive
weather event develops.�Thank you for your support of the Glacier Country Avalanche Center.
This message is
available via telephone at 257-8402 or on the internet
at www.glacieravalanche.org
DANGER RATING KEY
This advisory is also available on telephone hotline by calling:
Flathead Valley & Outside Montana -- 406-257-8402
Toll-free Within Montana -- 1-800-526-5329
Report your avalanche observations and incidents here
In an effort to improve our service to the public we are attempting
to define the users of this advisory message. Please contact us
with a message listing your backcountry interests. Are you a snowmobiler,
snowboarder, mountaineer, snowshoer, or skier? Also let us know
where you reside.
This advisory best describes conditions at the time of its issuance. As
time passes avalanche and snow conditions may change, sometimes quite rapidly.
Elevation and geographic distinctions used are approximate and a transition
zone between hazards exist. Because of the general nature of the advisory,
each backcountry party will always need to make their own site and time
specific avalanche hazard evaluations.
Thank you for your continuing support of Northwestern Montana's Glacier
Country Avalanche Center.
