SAN RAMON -- Over 7,700 residents and businesses in San Ramon were without power after a massive outage Friday afternoon, a PG&E spokeswoman said.

The outage was reported around 3:05 p.m., said Tamar Sarkissian of PG&E. What caused the power to go out is still unknown, Sarkissian said, and while originally 7,739 were without power, only 49 customers as of 5 p.m. awaited power restoration.

The area affected by the power outage runs west along San Ramon Valley Boulevard from Pine Valley Road to North Canyon Road, and the area along Bollinger Canyon Road from Crow Canyon Road to the area south of North Canyon Road.

The outage comes on the first of two days where East Bay residents are attempting to deal with spikes in warm weather, with temperatures reaching the 90s in San Ramon on Friday.

Check back for updates.

Contact Katie Nelson at 925-945-4782 or follow her at Twitter.com/katienelson210.