MERRIMAC, Wis. (AP) -- Officials from a Wisconsin resort that runs a ski lift that malfunctioned and injured 14 says the accident's cause couldn't have been predicted.

A packed ski lift at Devil's Head Resort near Merrimac suddenly ran backward on Dec. 17.

In a statement, the resort indicated the main cause was a massive failure of the chairlift's gearbox, which powers the lift. Without the gearbox, the lift's brake was inoperable.

Devil's Head General Manager Joe Vittengl (VITT'-ehn-gehl) says all the lifts are being re-inspected, including the one that malfunctioned. He says it's being repair and expects it to return to service by Wednesday.