CONCORD — A sudden and "major" snow and ice event caused about 50 accidents and closed sections of Interstates 89 and 93 north and west of Concord for several hours overnight Friday, state police said.

Troopers said the majority of the accidents were minor and involved motorists driving off the roads. The sections of the interstates were closed until early Saturday after the roads were treated by the state Department of Transportation, police said.