Updated, 6:09 a.m.

Drivers should expect delays during the morning commute in Montgomery County because about 200 traffic signals in Rockville, Gaithersburg, Germantown, Damascus and Derwood are not synchronized, according to Montgomery County fire officials.

Drivers are advised to take public transportation.

Original post:

A small cluster of thunderstorms wreaked havoc on traffic lights Tuesday night across Montgomery County, causing dozens of minor traffic accidents, police officials said.

Between 80 and 100 signals lost power or were malfunctioning and police were called to respond to at least 30 accidents, officials said. But Pepco reported only a few outages.

The National Weather Service said the storms were not severe, but heavy rain was reported across a small area.

No serious injuries were reported.