There's typically a spike in drunk driving-related deaths during December due to holiday revelry, according to a press release put out by the Hennepin Co. Sheriff's Department. Hence the crackdown's timing.
Not-so fun facts: One out of every eight Minnesotans has a DWI on their record, according to the department. Once you factor in insurance costs and legal fees, a DWI costs about $20,000 (ouch). You could argue that mass MADDness has sentimentalized the issue, thereby pushing our DWI laws to preposterous, draconian levels... but then you'd be an insensitive asshole.