BURTONSVILLE, Md.—Three people were killed and another person is in critical condition after a vehicle crashed in the back of a snowplow in Maryland on Monday evening. WUSA9 reports that according to Pete Piringer, chief spokesman for Montgomery County (MD) Fire & Rescue, the crash happened on northbound Route 29 Columbia Pike in Burtonsville, Maryland, about 25 miles (40 kilometers) southwest of Baltimore, at 6:45 p.m. Three of the victims were trapped in the vehicle following the crash. The roadway was shut down as crews worked to free them. Piringer said on Twitter that all three people were extricated from the vehicle just after 7 p.m. Two women and one man were pronounced dead at the scene. Another man was taken to a hospital in critical condition. None of the victims have been identified but police said they believe all four were adults. WJLA-TV reports that the Montgomery County Department …