Colorado Avalanche Bulletins

This bulletin is from the CAIC, which is an agency of the State of Colorado.

Colorado Avalanche Information Center (CAIC) Advisory

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Issued 03/20/2010 6:27 AM by John Snook

Highlights

Heavy snows on the east side of the Park Range and strong winds elsewhere have created a wide variety of surface snow conditions across the zone. You will need to evaluate your local area for instability.

Areas that have gained wind slab greater than 8" deep are most suspect.

Watch for signs of instability such as recent avalanche activity and propagating cracks.

Snow and wind created a wide variety of conditions across the zone. Use caution where wind slab developed.

The avalanche danger for the Steamboat zone is with pockets of on all aspects above treeline. Use caution in localized areas where wind slab has developed to greater than 8 inches. Near treeline the danger is and below treeline the danger is

Please send us observations anytime you are in the backcountry.

Snow & Avalanche Discussion

The wind direction changed from southwest to northeast around 5am Friday, which had dramatic effects on the Steamboat zone depending on location. For most areas around the zone that reside west of the Continental Divide, about 3-5" of snow fell prior to the wind shift and then precipitation cutoff after. Wind speeds increased dramatically with gusts exceeding 50 mph at times. For areas of the Park Range east of the Continental Divide, northeast winds generated heavy upslope snow. The Zirkel automated Snotel weather station recorded a 15" gain in height of snow.

Our observer on Friday in the Hahns Peak area found 3-5" of new snow and lots of wind effect. The new snow came in warm and bonded well with the old snow surface. Little sluffing of the new snow was found, although developing wind slabs showed some cracking and a little movement. As of Friday, the underlying snowpack was still wet as it was not cold enough to freeze and the storm snow likely acted as an insulator. Colder temperatures Saturday morning likely helped to freeze the snowpack, but it will warm quickly as milder temperatures return on Sunday.

The recent weather has created a wide variety of surface conditions for Saturday. The avalanche danger has trended upward where storm snow and wind load has developed into slab. You will need to manage your terrain based on local conditions. Steep slopes with a new slab greater than 8" are the most likely to slide. Recent avalanche activity, cracking and especially cracks that propagate are instability signs telling you to avoid steep terrain in your area. Temperatures remain seasonably cold on Saturday, so wet slide activity will not be an issue today.

Weather Discussion

A trough of low pressure is moving southeast out of Colorado this morning. Associated moisture was stubborn to leave some mountain locations, such as the Northern San Juans, but any remaining clouds will dissipate by mid-morning. Sunny skies will give way to scattered afternoon clouds. Northerly flow will keep temperatures seasonably cool. Clear skies tonight contribute to a cold start on Sunday. High pressure approaching from the west and mostly sunny skies allow temperatures to rebound nicely with high temperatures about 15 degrees warmer. Winds back to westerly on Monday, temperatures remain mild, and afternoon clouds increase in advance of the next storm system.

Unsettled weather is likely for Tuesday and Wednesday with more mountain snow.

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