A blown transformer sparked outages in Shrub Oak due to the storm that ripped through Westchester and the Hudson Valley Thursday.

The blown transformer also caused a road closure on Old Jefferson Valley Road. 

Witnesses say at first they thought the sound was from thunder.

MORE: Severe storm pounds Hudson Valley, taking down trees and power lines
MORE: News 12 Weather Center

"Around like 7 all of a sudden the lights flickered and we heard like a boom and then the lights flickered again and then all of a sudden it blew like fire and erupted," says Eileen He, an employee at No. 1 One Chinese Kitchen.

At the height of the storm, more than 15,000 people lost power in Westchester and the Hudson Valley. That number is now down to just under 11,000 outages across the area.