MONTEREY (CBS SF) — Thousands of utility customers in Monterey County were without electrical service Sunday afternoon due to a massive outage, according to PG&E.

According to PG&E spokeswoman Jacqueline Ratto, roughly 55,700 customers lost electrical service around 9:30 a.m. The outage is affecting customers near the Monterey Bay in Monterey, Sand City, Seaside, Pacific Grove, Castroville and Carmel-by-the-Sea.

While the exact cause of the outage is still under investigation, Ratto said, it may be associated with a high-voltage transmission line that came down near Moss Landing around 7 a.m.

As of 12:15 p.m. there was no estimate for when power would be restored, but technicians are working to bring customers back online using alternate power sources, according to Ratto.

© Copyright 2015 by CBS San Francisco and Bay City News Service. All rights reserved. This material may not be published, broadcast, rewritten or redistributed