AVY FORECAST 3.5.X
Backcountry Avalanche Forecast for Front Range
Issued 03/05/2010 7:10 AM by Spencer Logan
Highlights
Friday starts with cloudy with a dusting of snow. Southerly winds were at good speeds for snow transport overnight. Fortunately, the south facing fetches where the winds would pick up snow are crusted over, and there is not much snow available to drift. You may find thin slabs on northerly aspects near and above treeline, and they will be resting on powdery near surface facets. Today's clouds and cool temperatures will reduce the potential for warming and associated avalanches. It's back to buired weak layers and that hard-to-trust layer of facets at the ground.
Avalanche Danger
The avalanche danger for the Front Range zone is MODERATE above treeline. There is still the potential for isolated large, deep avalanches. Near treeline the danger is CONSIDERABLE on northwest, north, northeast, and east aspects. There is still the potential for isolated large, deep triggered avalanches, and you may find fresh, thin windslabs. The danger is MODERATE on other aspects near treeline, and all aspects below treeline.
Snow & Avalanche Discussion
Triggered avalanches have the potential to be deep and large near and above treeline. The snowpack is gaining strength above treeline, indicated by improving test scores and a decrease in reported avalanche activity. The dusting of snow overnight and this morning will have little impact on stability, but fresh slabs will thicken up this afternoon with the additional snow. Wind and sun shelters slopes have some nice recrystalized powder--near surface facets--under the dusting of new snow. You will find breakable sun and wind crusts on exposed slopes.
Near treeline is the most problematic elevation band. You may find thin, new slabs on northwest, north, and northeast aspects this morning, and they will be resting on near surface facets and surface hoar. Shallow but sensitive. There are older, deeper problems to consider, a lot of weak snow intermixed with crossloaded slabs. The Sunday/Monday cycle was most active in this band. Nine to 18 inches of snow fell, centered around Berthoud Pass, was followed by a rapid warm-up. Deep natural and triggered avalanches ran on northerly aspects. Westerly aspects were catching people off guard; a weak, shallow snowpack was heavily loaded. Since then, the slab has settled and stiffened, which makes them harder to trigger but propagate wider. East, south, to southwest aspects will have a sun crust under the dusting of snow. Today's cold temperatures and cloudy skies will keep it mostly locked up.
Below treeline you will find weaker snow on shady slopes, but much less crossloading and wind effect than the near treeline band. That limits the potential slabs. Sun exposed slopes will have thicker crusts.
Recent storm cycles, regardless of snow amounts, have brought on avalanche cycles across the Front Range zone. Remotely triggered, human triggered, and natural avalanches have spiked upwards with as little as 3 inches of new. New snow is in the forecast this evening, with clearing and warming for Saturday. Look for increasing avalanche danger by Saturday