This is Tony Willits with the backcountry avalanche advisory for the
Glacier Park and Flathead and Kootenai National Forest areas issued at 8:00
AM, Tuesday, March 12, 2002, by Northwestern Montana's Glacier Country
Avalanche Center.
HAZARD ANALYSIS:
The avalanche danger is currently being rated as High. This danger rating
expires after midnight, Tuesday, March 12. The outlook for Wednesday
through Thursday is for the avalanche danger to decrease if temperatures
stay below freezing and snowfall accumulations are light.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.

WEATHER ANALYSIS:
Since Friday the warmer westerly flow has brought in new significant
accumulations of snowfall to most locations. Snow water equivalents (SWE)
ranged from 1.0 to 3.6 inches through out Northwest Montana according to
sensors at the electronic sites from Friday through Monday.   In the past
twenty-four hours SWE have ranged from 0.3 inches to 2.4 inches.  This was
equating to only 1? to 8? of new snow that has a high water content.
Within the advisory area the Kootenai and Middle Fork of the Flathead
received the significant increases in SWE.

Temperatures have warmed significantly from last week?s artic influence.
Only a few sites are recording freezing temperatures over Monday night.
Daytime temperatures on Saturday were in the upper twenties and moderated
to the low to mid thirties by Monday.

Recordings from wind speed indicators from atop Big Mountain were averaging
15 to 17 mph from Sunday through Monday. Winds decreased late Monday and
early Tuesday but started to pick up again to averaging 20 mph early on
Tuesday morning with a gust at 57 mph around 5 am on Tuesday.  Winds have
been primarily out of the SW until early Tuesday morning and they maybe
making a shift and come from the W.

SNOWPACK ANALYSIS:
Our field observations on Monday were from the Kootenai National Forest,
and the Middle Fork of the Flathead on the Flathead National Forest and
from the Many Glacier area in Glacier National Park.  We had a single
observation report from the Marion Lake area in the Middle Fork of the
Flathead drainage.

Small point releases and roller ball activity was observed on steep
portions along the Middle Fork highway corridor around midday on Monday. An
avalanche did occur at 5:15 pm on Monday at Shed 4 and buried both tracks
and was approximately 50 yards wide and three foot in depth.  This path is
behind the Snowslip Inn.

Tremendous loading is occurring within the surface layer of the snow pack
especially below 6000?.  The surface layer of the snow pack is tending to
move faster than layers below and when associated with the buried melt
freeze layers instability will occur.  This will be especially true where
significant refreezing does not occur.

Wind loading is more significant at higher elevations especially with the
new and predicted heavy accumulations.

AVALANCHE - INSTABILITY DESCRIPTION:
The avalanche danger is currently being rated as HIGH.  Unstable slab
layers are likely on variety of aspects and slope angles.  Both natural and
human triggered avalanches are likely. Travel in avalanche terrain is not
recommended.  Safest travel is on windward ridges or on lower angle slopes
without steeper terrain above.

WEATHER FORECAST & AVALANCHE OUTLOOK:
A moist Pacific system will bring heavy snow to areas of Northwest Montana
above 5000 feet over Monday night and early Tuesday morning.  Snow levels
will be lowering to 3000 feet Tuesday and gusty winds will cause blowing
and drifting snow at times.  Cooler and unsettled weather will continue for
the remainder of the week but snow accumulations should be fairly light.

Above 6000? elevation on Tuesday expect 8 to 14 inches of new snow with 2
to 4 inches expected on both Wednesday and Thursday.

Mountain maximum air temperatures should be 20 to 30 degrees Fahrenheit
through the period.

Mountain winds Tuesday are forecasted to be 20 to 30 MPH out of the W.
Expect W winds on Wednesday and Thursday at 15 to 25 mph.
The next regularly scheduled update of this advisory message will be on
Friday, March 15, 2002.

Please note that this avalanche advisory is our best interpretation of snow
pack conditions and National Weather Service forecasts on the day this
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.


Tony Willits
Swan Lake Ranger District
(406) 837-5546