Santa Rosa Memorial Hospital will be running on backup generators for several hours late Sunday and early Monday as PG&E crews repair equipment following several power failures last year.

Patients with traumatic injuries likely will be sent to other hospitals during the hours when Memorial, Sonoma County's trauma center, is on the backup power.

The emergency room will remain open and many services will be uninterrupted. But Memorial will not perform surgery, cardiac catheterization or other invasive procedures unless the emergency needs of a patient make it too risky to send the patient elsewhere, hospital spokeswoman Katy Hillenmeyer said.

PG&E crews will cut power and the hospital will run on generators starting at about 7 p.m. Sunday until about 5 a.m. Monday, although the exact times could change.

PG&E will be upgrading and making essential repairs to circuits "that power the hospital and which are likely, if not reinforced or replaced, to cause unplanned outages in the future," according to a statement by the hospital.

It was unclear whether the repairs and upgrades will involve equipment that led to repeated power failures at Memorial and the surrounding neighborhood in November and December.

PG&E couldn't immediately be reached Sunday.

Hillenmeyer said the repairs are taking place on hospital grounds.

Four blackouts in a 24-hour-period Nov. 15 and 16 prevented at least three trauma patients from receiving treatment at Memorial. The patients, who included a stabbing victim and a pedestrian hit by a van, were flown to out-of-county hospitals while Memorial was on generator power.

The blackouts also hit neighborhood residents and businesses, including several medical offices left in the dark.

When the first power failure struck, PG&E crews tried to re-distribute customers to other circuitry routes, causing some circuits to overload and leading to successive blackouts, PG&E said at the time.

An underground equipment failure caused a blackout Dec. 21 for about 1,400 homes, businesses and the hospital. A swath of Santa Rosa from Highway 12 to Santa Rosa Creek and from Santa Rosa Avenue to Yulupa Avenue went dark.

Hillenmeyer said nearby hospitals and ambulance crews have been alerted that patients may be diverted from Memorial to the other hospitals until power is fully restored.

You can reach Staff Writer Julie Johnson at 521-5220 or On Twitter @jjpressdem.