Actually, it broke in half as the result of losing a blade and vibrating considerably, causing Transalta Utilities, the owner, to shut the whole section of towers down for inspection. Fort MacLeod's MacLeod Gazette published a story on the incident on March 06 2012. Some excerpts are below.
DAVID THOMAS, GAZETTE CONTRIBUTOR
Canada’s original wind farm along Cowley Ridge remains shut down for intensive structural inspection following the spontaneous self-destruction late Friday of one of its 18-year-old turbines.
System operators at TransAlta Corporation’s Calgary control centre were alerted by remote fault sensors that one of the Cowley Ridge turbines was vibrating unusually.
They immediately shut down the entire fleet of 57 turbines mounted atop 80-foot steel lattice towers — a design since replaced by the more familiar welded tubular towers.
Technicians dispatched to the scene from TransAlta’s Pincher Creek maintenance depot discovered that one of the three black fiberglass blades had broken off while the turbine was generating power.
When they returned the following morning they discovered that the bolted steel tower itself had buckled overnight, apparently after being weakened by the impact of the errant blade.
From the MacLeod Gazette