Whistler Blackcomb is warning mountain users to stay out of closed areas as they can be hazardous.
"Winter operations on Whistler Mountain are now closed for the season and Blackcomb Mountain will close on May 30," said Bernie Protsch, the Ski Patrol Manager at Whistler Blackcomb.
"It has come to ski patrol's attention that since Whistler has closed people have been skidooing up the mountain into the alpine where there is currently a high avalanche risk due to the spring conditions.
"This is a huge safety concern for Whistler Blackcomb. Both Whistler and Blackcomb Mountains are private property and accessing the terrain outside of operational hours is considered trespassing.
"Whistler Blackcomb asks that no persons enter the closed areas of the mountains for their own safety and for the safety of the Whistler Blackcomb staff."
So far no one has been hurt but there are numerous potential natural hazards in the areas that may not be identified or mitigated when the mountains are shut down for off-season maintenance, said Protsch.
Currently there are two "persistent weak layers" buried in the snowpack, as well as significant overhead hazard from cornices.
The current trend of a wet spring snowpack is expected to re-awaken these deep weak layers, and Whistler Blackcomb is expecting to see some deep slab avalanche activity this spring. It is likely that the type of avalanche that will result from a deep failure will run far with significant destructive potential. Recently even small triggers have resulted in wet avalanches running for unusually long distances and moving significant amounts of snow.
Mountain staff is asking backcountry enthusiasts to please respect the safety of staff working on the mountains by staying off Whistler Blackcomb terrain when closed.
Unauthorized activity has the potential to disrupt maintenance operations by threatening staff safety or distracting resources from their scheduled tasks.