This is Tony Willits with the backcountry avalanche advisory for the
Glacier Park and Flathead and Kootenai National Forest areas issued at 7:30
AM, Friday, March 15, 2002, by Northwestern Montana's Glacier Country
Avalanche Center.
HAZARD ANALYSIS:
The avalanche danger is currently being rated as CONSIDERABLE. This danger
rating expires after midnight, Friday, March 15. The outlook for Saturday
through Sunday is for changing weather and the potential of escalating
avalanche danger.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 Tuesday snow water equivalents (SWE) ranged from 0.4 to 1.4 inches
through out Northwest Montana according to sensors at the electronic sites
from Wednesday through Thursday.   This was equating to 2? to 9? of new
snow.

Temperatures decreased through the period from our warm Monday.
Temperatures ranged in the twenties at most sites with some mid teens for
lows on Thursday.

Wind speeds declined on Wednesday and Thursday from the stronger winds
early in the week.  Recordings from wind speed indicators from atop Big
Mountain ranged from 9 to 14 mph from Tuesday through Thursday. Winds have
been out of the SW and W.

SNOWPACK ANALYSIS:
Our field observations on Thursday were from Allen Peak in the south end of
the East Cabinets on the Kootenai National Forest, from the southern
Whitefish Divide area on the Flathead National Forest, from the Marias Pass
and Many Glacier areas in Glacier National Park.  We had a single
observation report from the east front on the Lewis and Clark National
Forest.

On Tuesday it was mentioned that a slide occurred over the old burned out
shed 4 east of Essex.  Upon further observations several natural avalanches
occurred along the Middle Fork corridor.  Goatlick, Hanging Tree and the
I-Beam paths all slid as well as three more paths that approached or
reached the tops of snowsheds along the railroad tracks.  Natural slides as
well as skier triggered slides were reported and observed outside of the
Big Mountain boundaries.  Natural avalanches were observed in the Cabinets
as well.  No doubt that there were more naturals that slid throughout the
advisory area during this period but have been yet to be observed.

The snow pit observations were finding easy failures in the top thirty to
seventy centimeters of the snow pack over varying thickness of melt freeze
layers.

Affects from the wind loading that we received early this week are still
lingering over the area.

AVALANCHE - INSTABILITY DESCRIPTION:
The avalanche danger is currently being rated as CONSIDERABLE.  Unstable
wind slab layers are probable on steep terrain, especially on wind-loaded
slopes.  Natural avalanches are possible, while human triggered avalanches
are probable.  Backcountry travelers should be cautious in steeper terrain.
Be aware of potentially dangerous areas of unstable snow.  These
instabilities are going to be driven primarily by new snowfall, often
accompanied by strong winds.

WEATHER FORECAST & AVALANCHE OUTLOOK:
Cool moist northwest flow will continue to bring snow to our area Friday.
A cold system is predicted to drop south from Canada this weekend bringing
potentially heavy snowfall and colder temperatures.

Friday 4 to 8 inches of new snow is predicted with 6 to 12 inches expected
on Saturday and 4 to 8 inches on Sunday.

Mountain maximum air temperatures should be 20 to 30 degrees Fahrenheit on
Friday.  Saturday maximum temperatures are predicted to be 15 to 25 degrees
Fahrenheit. While Sunday temperatures are colder yet with temperatures
predicted to be 10 to 20 degrees Fahrenheit.

Mountain winds Friday are forecasted to be 15 to 25 MPH out of the W.
Expect SW winds on Saturday 20 to 30 mph. SW winds at 15 to 25 mph are
predicted for Sunday.

The next regularly scheduled update of this advisory message will be on
Tuesday, March 19, 2002.

On Saturday, March 23 the avalanche center will be hosting the next
installment of our public avalanche awareness training.  This is a
continuation of the program we began in January, continued with the
February 23rd session and will end this winters round of awareness sessions
on March 23rd.  This field session will meet at 8:15 AM at the base of
Chair One, the Glacier Chaser, at the Big Mountain.  The session will focus
on the more variable conditions of spring, we think.  For more information
please call Stan Bones in the evenings at 837-6022.

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