Colorado Avalanche Information Center Bulletin

This is Denny in the Avalanche Center at 7:30 am, Wednesday, February
6, 2002.

DISCUSSION

Pretty quiet weather wise, clear and cold overnight at many mountain
sites. Today, high pressure and warm temps will continue to dominate.
Tomorrow, continued dry and warm but increasing clouds as the ridge
flattens and the flow becomes more westerly. Weather will change on
Thursday night as a Pacific system moves in on a NW flow bringing
increased clouds, strong winds ahead of the front to the N and C mtns.
The strongest winds will be east of the Divide along the Front
Range.   The forecast details:

Northern Mountains

Wednesday: Clear. Winds N-NW/15-20. Highs 18-28. Lows 5-15.

Thursday: Mostly clear, increasing clouds late. Winds W/10-20 G30 abv
TL. Highs 22-32. Lows 0-10.

Friday:  Cloudy. Chance for snow. Increasing winds W-SW/20-30G50.
Highs 25-35.

Central Mountains

Wednesday: Clear. Winds NW/10-20. Highs 23-33. Lows 0-10.

Thursday: Mostly clear, increasing clouds late. Winds W-SW/10-20 G30
abv TL. Highs 27-37. Lows 0-10.

Friday:  Cloudy. Chance for snow. Winds W-SW/20-30G50. Highs 25-35.

Southern Mountains

Wednesday: Clear. Winds NW/5-15. Highs 23-33. Lows -5 to +5.

Thursday: Mostly clear, increasing clouds late. Winds W-NW/10-20 G30
abv TL. Highs 27-37. Lows 0-10.

Friday:  Cloudy. Windy abv TL, W-SW/20-30G50. Highs 25-35.

SNOWPACK

No slides have been reported for the last two days. Depth Hoar makes
up nearly our entire snowpack, with hard and soft slabs resting on top
on many N-SE aspects. This and other near surface faceted layers will
persist longer than any other kind of weak layers. Many avalanche
professionals experience has been to "never trust a depth hoar
snowpack".  Be sure to do your favorite stability tests for depth hoar
and do lots of them in representative places. My favorites are the
rutschblock test and compression tests. Remember, depth hoar
avalanches can be triggered from shallow/weaker areas of the snowpack,
like a rock outcrop in the middle of the slope.

The backcountry avalanche danger is rated:

N mtns, C Mtns, and W San Juans: MODERATE near & above treeline,
especially on N-SE aspects steeper than 35 degrees. Below treeline,
LOW with pockets of MODERATE on slopes steeper than 35 degrees.

E San Juans: Overall LOW, with pockets of MODERATE N-E aspects steeper
than 35 degrees.

Hogan