CBAC Avalanche Bulletin issued 11/25/14
Mark your calendars! CBAC Annual Avalanche Awareness Night is December 6th. The CBAC Beacon Brush up is December 7th at the Town Park. Look for more information to follow.
This report is brought to you by Black Tie Ski Rentals.
We will see one more shot of light snow today before clear skies return for the holiday. Triggering windslabs and persistent slabs will be likely today near and above treeline, and possible below treeline.
Yesterday, orographic forcing and convection from daytime heating contributed to spur light to moderate snow most of the day, dropping 3-6” in the mountains above Crested Butte accompanied by northwest winds in the 10-20 mph range.
Temperatures currently sit in the single digits, and Northwest winds are increasing ahead of today's next wave of snow from British Columbia. Although the mountains north of I-70 look to be favored, the higher elevations of the Elk Mountains should scrounge another 3-6” and possibly more in Schofield area by Wednesday afternoon.
Settled storm totals since Saturday range from 15” at Irwin, 13” at Schofield, 13” at CBMR . Most of this snow fell quite powdery and unconsolidated, and over time has gained cohesiveness. Backcountry travellers are beginning to see the storm snow behaving more like a slab, with cracking seen in the new snow and large collapses generated on deep facets near the ground. On sunnier, South and West facing slopes, there is a stout melt-freeze crust below the new storm snow which was failing under moderate loading steps (elbow taps) in stability tests and could become a problematic bed surface in the future.
Today, we will get another round of new snow accompanied by increasing Northwest winds. Windslabs ranging from 1-3 feet deep in lee and cross-loaded terrain will be easiest to trigger today, but those deeper persistent slabs with greater propagation and consequence will be most concerning and dangerous. Dig down on representative aspects and elevation of the slope you wish to travel, and look for the presence of “greyer,” coarser, sugary grains near the ground. If these grains are present, odds are good that they rest on most other similar slopes as well.
Don't let cold temperatures rush your decision making today. Travel with a plan, and carefully evaluate the snowpack for persistent weak layers and the density and texture of the snow under your feet or sled. Although the snowpack has been gaining strength little by little, this is the fourth consecutive day of snow, and some slopes may be near their tipping point.
Reported by: Ian Havlick
We have started daily advisories, look for the day's bulletin by 7 a.m each day til May!