Colorado Avalanche Information Center

Public Forecast of Weather and Backcountry Avalanche Conditions

This is Nick in the Avalanche Center with current information on
mountain weather, snow and avalanche conditions posted at 7:10 am,
Sunday, February 24, 2002.

DISCUSSION

A weak weather system is moving into CO this morning but moisture is
not abundant. This should bring only light snow to the N&C mtns and
possibly scattered showers to the W San Juans, little if anything to
the E San Juans. Look for increasing winds Sunday night onto Monday
with enough moisture to fuel orographics on a W-NW flow. Tuesday looks
to be drier but continued windy, and cold temperatures with a cold
fetch right out of Canada. The forecast details:

Northern Mountains

Sunday: Cloudy, light snow, 2-5". Winds NW/5-15 G20s higher ridgetops.
Highs 12-22.

Sunday night: Cloudy, showers to light snow, 1-3". Winds W/10-20 G40.
Lows 5-15.

Monday: Cloudy, showers to light snow, 1-3". Winds WNW/5-15 G30. Highs
2-12. Lows -10 to 0.

Central Mountains

Sunday: Cloudy, light snow, 2-4" but T-1" at Monarch. Winds NW/5-15
few G20s higher elevations. Highs 12-22.

Sunday night: Cloudy, showers to light snow, 1-3" possible. Winds
W/10-20 G40. Lows 7-17.

Monday: Cloudy, showers to light snow, 1-2". Winds WNW/10-20 G30s.
Highs 3-13. Lows -10 to 0.

Southern Mountains

Sunday: Partly-mostly cloudy, showers, T-2", Wolf Ck 0-T". Winds
NW/5-15 G20s higher ridgetops. Highs 10-20.

Sunday night: Cloudy, scattered showers, T-1". Winds WNW/10-20 G40.
Lows 5-15.

Monday: Partly-mostly cloudy, isolated showers possible. Winds
W-NW/10-20 G30s. Highs 5-15. Lows -10 to 0.

SNOWPACK

No fresh avalanches have been reported this morning. However, one
size-2 and several smaller naturals were observed in the Red Mtn Pass
area yesterday afternoon. Also, avalanche control work on Monarch Pass
produced a small avalanche that reach the road but was quickly cleaned
up. Warm temperatures helped stabilize the upper new snow in all mtns
yesterday but there are still weak layers to contend with in the lower
snowpack. We are still concerned about triggered releases on steep
slopes both above and below timberline. Yesterday in the S mtns around
Red Mtn Pass the snowpack was collapsing, cracking and shooting long
cracks under the weight of skiers. Collapsing was strong enough to
shake snow off of tree branches some 200 feet away from the skiers.
The main culprit there is a near-surface facet layer about 20-30 cm
below the surface. This provides a poor bond between the upper snow
layer and the old snowpack. Fragile depth hoar grains can be found
below this weak layer.  There may be a few natural releases in the S
mtns but none expected in the N&C mtns except in an isolated case on
terrain steeper than 35 degrees. Backcountry travelers should use
extra caution on any slope steeper than 30 degrees. Where you
encounter the signs of a weak snowpack (such as cracking and
collapsing mentioned above) move to more gentle terrain, less than 30
degrees, and enjoy the skiing and snowboarding there without the worry
of triggering a slide.

BC danger ratings:

N mtns, C mtns ... overall MODERATE with areas of CONSIDERABLE,
especially above 11,000 feet.

W San Juans  ... Red Mountain Pass area, from Silverton to Telluride
to Ouray, CONSIDERABLE with pockets of HIGH. Elsewhere in W San Juans
... MODERATE with pockets of CONSIDERABLE.

E San Juans ... generally LOW with pockets of MODERATE on N-E aspects
35 degrees and steeper.

Logan