Sunday, January 27th, 2002

Good morning, this is Scott Schmidt with your Gallatin National Forest
Avalanche Advisory issued on Sunday, January 27th, at 7:30 am.  A
Snowmobile Safety Grant from Montana Fish, Wildlife, and Parks is the
sponsor for today's advisory.  This advisory does not apply to operating
ski areas.

                CURRENT CONDITIONS AND WEATHER DISCUSSION:

Rise and shine you sledheads.  Up and at um' all you sliders.  It's a
powder day!  It snowed in the southern mountains all day yesterday with
accumulations of 10-12 inches in the Lionhead area and the mountains 
around Cooke City.  The northern mountains started getting snow late last 
night and are catching up with 7-9 inches at all ski areas.  Winds blew hard 
most of yesterday but have dropped off overnight with ridge-top winds blowing 
10 - 15 mph from a westerly direction.  The good news is more snow!  It will
continue to snow through most of the day with additional accumulations 
of 4-6 inches in the northern mountains and 6-12 inches in the south, with 
the heaviest snowfall in the Cooke City area.  Ridge top winds will pick up
again, blowing 20-30 from the west/southwest.  Temperatures will be warm
today with mountain highs in the low 20s but a cold, artic air mass is
moving into our area and this will send the overnight low temperatures 
into the basement.

                    SNOWPACK AND AVALANCHE DISCUSSION:

The Bridger Range, and Northern Gallatin, Northern Madison, and Washburn
Ranges, and the mountains around Cooke City:

The northern mountains experienced yet another day of strong winds
yesterday with ridge-tops gusting into the 40s.  It has been blowing like
stink for several days now but, with no new snow, I wouldn't expect there
to be much transport.  In the absence of a widespread weak layer, the
avalanche concern today will be the rapid loading associated with the new
snow.  It has been snowing an inch an hour for the past 9 hours in the
northern mountain ranges.  This rapid loading tends to be a bit unstable
until the snowpack can adjust to the new load.  This storm came in fairly
warm so we can expect the new snow to bond quickly to the old snow surface,
however I'll bet you can trigger some decent little avalanches on steep
slopes, especially those that get additional load due to wind.

The mountains around Cooke City have gotten 2-3 feet of snow in the past 
4 days, and strong winds.  As with the Bridger Range, these mountains are
blessed with a stable snowpack that can handle this kind of load, there
fore deep instabilities are not the concern.  Any time you pile 12 inches of
snow onto a slope in 24 hours you can anticipate instabilities in the new
snowfall and wind-loaded slopes will be extra sensitive.

For today, I feel the avalanche danger in these areas will be CONSIDERABLE
on all slopes steeper then 35 degrees.  On all other slopes I consider 
the avalanche danger to be MODERATE.  Pay particular attention to wind loading
that occurs throughout the day.

The Southern Gallatin, and Southern Madison Ranges, including the Lionhead
area near West Yellowstone:

The Lionhead area received 10-12 inches of snow yesterday and an observer
in the area reported lots of wind with the new snow.  This new snow falls
on a snowpack that is laced with pockets of buried weak crystal known as
surface hoar.  Given the rate at which the snowpack has loaded and the
recent strong winds, I feel these pockets may become active today.
Evidence of the instability associated with the recent wind loading comes
from two separate groups skiing in the Bacon Rind drainage.  Both parties
experienced collapsing and cracking of the snowpack in wind loaded areas
and one party triggered a small avalanche 1-2 feet deep on a relatively low
angle slope.  Given there are pockets of weak snow in the southern mountain
ranges, I consider today's avalanche danger HIGH on all wind-loaded slopes
steeper than 35 degrees and CONSIDERABLE on all other slopes.

                          ADDITIONAL INFORMATION:

Sad news from the Bitterroot Mountains west of Missoula where 4
snowmobilers were killed in an avalanche yesterday.  Reports are still
sketchy and we'll fill you in as we get more info.

The next advisory will be issued tomorrow morning at 7:30 am.

END