Reuters – A squirrel knocked out power for some 45,000 energy customers in the San Francisco Bay area on Monday, according to officials and the local Contra Costa Times newspaper.

Pacific Gas and Electric Company said on its Twitter account that service had been restored for virtually all those affected by the outage about 10:15 p.m. local time, but it did not provide a cause for the disruption.

PG&E spokesman J.D. Guidi told the Contra Costa Times that power was down in cities east of San Francisco, including Berkeley and Oakland, on Monday night after a squirrel "impacted equipment" at the El Cerrito substation. He gave no details.

The downtown Berkeley station of the Bay Area Rapid Transit system was closed for several hours on Monday due to the outage, the agency said on its Twitter account.

Cities to the south, including San Jose, also suffered outages on Monday that Guidi said were caused by equipment failures due to triple-digit temperatures.