UPDATE 2 (1:10 p.m.): Coldwater Canyon Avenue has reopened to automobiles.

UPDATE 1 (11:30 a.m.): Coldwater Canyon Avenue remains closed to automobiles except for school-related business as work crews continue to clean mud and debris.

Due to water damage from Mulholland Drive to Ventura Boulevard, Coldwater Canyon Avenue is closed. School is still open, but all vehicles must enter the campus from the north. Advanced Placement Human Geography and AP Microeconomics are delayed until 9 a.m., and AP Latin is delayed until 1 p.m. School will begin at 8:35 a.m., and each period will last 40 minutes instead of 45.

Harvard-Westlake security personnel are positioned at the corner of Ventura and Coldwater to allow cars to turn onto Coldwater.

A single-car accident damaged a water main overnight, causing mud and water to flow onto Coldwater, security guard Mark Geiger said. The crash broke off a fire hydrant on Coldwater around 2 a.m., the Los Angeles Daily News and KABC reported.

“I really don’t think it was necessary to delay APs because the policemen on Coldwater are completely letting Harvard-Westlake kids through first of all, and second of all, if you don’t get here on time you can still take the AP next Thursday on the make-up day, so I feel like this is unnecessary and it’s actually hurting my schedule because I have a doctor’s appointment later, and I’m worried it’s going to interfere with that,” Megan Cohen ’17 said.

Head of School Jeanne Huybrechts signed an email sent by the school’s emergency notification system at 5:41 a.m. to inform the students, parents and faculty.

The school also sent out a text message at 5:40 a.m. and a call at 5:44 a.m.

Clean-up crews estimate Coldwater will reopen between 8 and 9 a.m.