SANTA ANA (CBSLA) — Health officials across the Southland are warning the public to be wary during this intense flu season that has some hospitals rerouting patients due to their increasingly limited capacity.

From Laguna Beach to Long Beach, emergency rooms were struggling to cope with the overwhelming cases of influenza and had gone into “diversion mode,” during which ambulances are sent to other hospitals.

O.C. Global, one of Orange County’s busiest hospitals, announced Thursday afternoon it would no longer be accepting ambulances at its emergency room, except for those transporting trauma patients.

“It’s not just Orange County, it’s all across the country,” internist Dr. Ray Casciari with St. Joseph Hospital told CBS2 News. “So, yes, this is going to be an epidemic year,” Casciari warned.

Earlier in the day, the City of Riverside held a press conference during which health officials addressed the “surge” in influenza cases during the last week in the city, as well as Riverside County.

Dr. Steven Kim, medical director for Riverside Community Hospital, said emergency room admissions for the flu were up 40 percent above the norm, though he said many of the patients suffered from “uncomplicated influenza,” meaning most of them would get better on their own with minimal medical attention.

However, people are susceptible to pneumonia, Kim said.

The surge has been in influenza A, or “cyclical” flu cases.

The Orange County Health Care Agency has logged at least 1,200 flu cases, more than double than what was seen in the first week of January 2016.

For the state, Dr. Casciani predicted this is an early spike in cases that will reach four times what it was at the same time last year.

Casciani also warned a sneeze contains up to 500,000 influenza germs.

Prevention, which includes washing hands and staying home if a person is sick, is key, most doctors say.

Though vaccines may not be 100 percent effective against the flu, they can “reduce the severity of the illness,” one Riverside health official said.

A person should head to the emergency room when symptoms include confusion, difficulty breathing, vomiting and uncontrolled fever.