As of Wednesday, April 23, 2003
An unrelenting layer of cloud that has been hanging on the local peaks for the past few weeks is expected to maintain its grip. Some brief thinning allowed the sun to get through just enough to trigger some significant avalanche cycles over the past four days. The cloud cover is expected to rebuild itself a little, but this will just slow the avalanche cycle.
A cycle of natural wet avalanches began to clean out many start zones with some thinning of the cloud on Saturday. Very mild temperatures persisted until Wednesday morning with many more natural wet avalanches being observed during this time, some digging down to the ground.
Light precipitation and slightly cooler conditions may mitigate the instability slightly over the next few days, however, not by much. While weak crusts have been forming with night time cooling, the underlying snow is moist and isothermal on all aspects except north facing ones above 1,900 metres. Any warming or thinning of the cloud cover will break this crust down quickly and likely trigger more slides. Soft slabs to size 2 have been triggered in lee start zones above 1,900 metres, so even here there is a hazard.
The familiar refrain of use caution when exposed to a cornice hazard still applies. Cornices this spring are relatively new with most of our winter snow having fallen since March began, and this immaturity coupled with the ongoing mild temperatures makes them as threatening as ever.
The avalanche danger rating for the backcountry adjacent to the Whistler-Blackcomb ski area on April 23, 2003 is moderate in the morning, however, warming is so significant that by mid-day the hazard is expected to be HIGH with natural and human triggered avalanches likely. Travel in avalanche terrain is not recommended.
Stay informed at www.avalanche.ca or call 604.938.7676 for updated information. Stay safe.