A water main break in Plymouth forced a west metro high school to call off classes about halfway through the school day Monday. Classes were expected to resume Tuesday.

A 12-inch pipe burst under E. Medicine Lake Boulevard between 34th and 36th Avenues N. just after 8 a.m. on Monday. The line feeds directly into Robbinsdale Armstrong High School and the Hazelden Center for Youth and Families.

Classes at Armstrong were dismissed at 11:30 a.m., when contractors began making repairs, shutting off water to the school. There was no damage to the school.

Water service to nearby residents was not affected, said Scott Newberger, a utility supervisor for the city of Plymouth.

It was not immediately known what caused the line to break, but Newberger said the cold may have been a contributing factor.

Tim Harlow