[1] In the episode, Stan and Cartman accidentally destroy a beaver dam, which causes a catastrophic flood in the nearby town of Beaverton.
To avoid punishment, the boys allow the townfolk to be misled into believing that the dam's destruction was caused by global warming, which triggers panic and mayhem around Colorado and across the country.
Cartman reveals that he lied about the boat belonging to his uncle and convinces Stan to try to hide their involvement by maintaining complete silence about the incident.
At a conference at the Governor's office with top Colorado scientists and government officials, they all declare that the disaster is the result of global warming.
The attempt is a disaster in itself, as they wind up crashing into an oil refinery, compounding the problems of the stranded people, who now must deal with drowning and fire.
Dressed in heavy arctic mountaineering gear despite the mild weather, the trio quickly collapse in the street due to heat exhaustion and dehydration, but mistake their symptoms as the "last stages of hypothermia."
In exasperation, Stan finally admits that he broke the dam, but one of the townspeople incorrectly interprets his admission as a lesson to stop obsessing over who to blame while ignoring the problem.
The townspeople all begin to declare, "I broke the dam", with Cartman joining in knowing that he won't get in trouble now, while Stan tries unsuccessfully to explain that he literally did it, with a boat.