Eighteen months after an Excalibur Gondola tower sheared off do to ice jacking the B.C. Safety Authority submitted its final report of the accident this week.
Whistler Blackcomb and other ski areas have already acted on most of the safety authority's recommendations.
"We (followed up on lift manufacturer) Doppelmayr's service bulletin that said we need to drill holes in towers, and did that last summer after the snow had melted," said Doug Forseth, senior vice-president of operations for Whistler Blackcomb.
"Now we do an annual check in the fall to make sure that the hole is not plugged up so any water in the tower can be drained. That's a part of our process now."
On Dec. 16, 2008, a tower supporting the Excalibur Gondola snapped and left 43 passengers trapped for over two hours in frigid temperatures until they could be evacuated by Whistler Fire Services ladder trucks, ropes and harnesses. Twelve people were injured, one with a broken vertebrae, when the cabins suddenly dropped more than 10 metres and bounced off roofs and parking lots.
The incident took place at roughly 2:15 p.m., before the afternoon rush to download to the village.
The cause of the incident was spotted almost immediately, once investigators saw the ice that had built up inside Tower 4. The ice had expanded as the temperatures dropped, first bending and then snapping the tower below the flange where two sections were welded and bolted together.
The process is known as ice jacking, and had been seen in the industry before. There was a warning to test for water after a lift tower burst at Silver Mountain Resort n Montana on Dec. 31, 2006. However, in the case of Excalibur's tower 4, where the tower tube was partially filled with concrete to provide dampening, it was difficult to check for water.
At the time the towers were supposed to be sealed and engineers were reluctant to drill drain holes into towers because that would provide a way for water to get in. As well, the tower itself was tested in the autumn using resonance equipment and passed an inspection with the B.C. Safety Authority, which among other things certifies and regulates all ski lifts in the province.
The B.C. Safety Authority attended the accident site with three investigators, including two millwrights experienced in lift construction.
With representatives from the lift manufacturer already in town for the opening of the Peak 2 Peak Gondola on Dec. 12, Whistler Blackcomb also did a full assessment of all of its lifts to ensure that they were free of ice. The Excalibur reopened on Christmas Eve, eight days after the tower collapse.