Two teams of engineers, one funded by the state of Louisiana and one based at the University of California, Berkley, have previously put the blame on the Army Corps of Engineers and on a weaklayer of ground below the canal walls.
Above-freezing temperatures also led to overflow along the trail, a potentially dangerous situation where water has pushed up through the ice and refrozen, creating a weak top layer of ice that teams and mushers can break through.
Essentially, they isolated a rectangular column from the surrounding snowpack and used a snow saw to start an artificial fracture by cutting through the weak underlying frost layer, then watched what happened.