A rare type of ice build has been blamed for the partial collapse of a gondola tower at Canada's Whistler ski resort.

Thirteen people were slightly injured and dozens were trapped for hours in unheated gondola cabins when a tower on the Excalibur gondola buckled Tuesday afternoon, bouncing two of the cars off the ground.

The resort, which will host the alpine events of the 2010 Winter Olympics, released a statement Wednesday indicating the tower failure occurred when water somehow seeped into a splice on a section of a tower.

An extreme deep freeze turned that water to ice, rupturing the splice in what the resort says is an extremely uncommon phenomenon known as "ice-jacking."

Those findings must still be confirmed by the British Columbia Safety Authority, but a spokesman for Whistler was confident a safety authority inspection would find no similar risk on any other lifts at the resort.

Doug Forseth expected all lifts on Whistler Mountain would be operating by Wednesday morning following the inspection, while operations on Blackcomb Mountain were expected to be back to normal by midday.