A large swath of Santa Rosa around Memorial Hospital and Montgomery Village lost power Friday morning for the fourth time in 24 hours, testing residents' patience and interfering with business at surrounding medical offices and shops.

About 1,000 customers lost power in Friday's 7:30 a.m. outage, PG&E spokeswoman Brittany McKannay said.

Santa Rosa Memorial Hospital was among them and switched automatically to back-up generator power when the lights went out, hospital spokeswoman Katy Hillenmeyer said.

The hospital, which includes the region's trauma center, went into diversion mode, but no trauma cases occurred before the power was back on at 10:15 a.m., Hillenmeyer said.

At least three trauma cases were transported by helicopter to out-of-county hospitals overnight as a precaution, since the hospital was operating on emergency generator, she said.

Traffic lights along busy Farmers Lane and elsewhere also were affected during the Friday morning commute, even as light rain snarled traffic, authorities said.

For Paul Moore, who works remotely from his California Avenue home as a software development support engineer for GE Healthcare, the successive outages proved a frustrating exercise in juggling to work around battery supply.

Several items from the family freezer also had to be tossed, he said.

Moore said a recorded call he received from PG&E on Friday apologizing profusely for the inconvenience did not make up for the interruption in power and the company's otherwise poor communication on the problem.

"The communication from PG&E regarding the circumstances was non-existent, as their web page does identify you have an outage but it gives no relevant information as to what is going on and when it will come back," he said.

The problems began around 9:30 a.m. Thursday when an underground equipment failure occurred, knocking out power to more than 1,000 customers in central Santa Rosa, McKannay said.

Crews distributed the load to alternative circuitry routes, but some circuits became overloaded, causing successive outages Thursday afternoon and Thursday evening.

The area includes numerous medical offices, many of which had to cancel appointments Thursday, though there were reports of a few patients being treated by flashlight.

Clerks at the Village True Value Hardware Store on Montgomery Drive near Summerfield Road reported a significant sale of heavy-duty, camp-style fluorescent flashlights and batteries — more than $300 worth — to Memorial Hospital on Thursday.

"We completely got cleaned out," clerk Daniel Bergeron said.

McKannay said all of PG&E's Santa Rosa-area crews were assigned to the outage and, by 1:35 p.m. Friday, had restored power to nearly all customers.

But she warned that crews would be continuing to make repairs in the area until about 7 p.m. Friday, raising the possibility of further interruptions.

PG&E also was providing generator power to about 12 residential customers closest to the site of the equipment failure on Glenwood Court, off Sonoma Avenue. Those customers, McKannay said, had been notified that they might experience a momentary outage when they were brought back onto the main system.