California is enlisting retired doctors and medical and nursing students to help treat an anticipated surge of coronavirus patients, the governor announced Monday.

The California Health Corps effort comes as the nation’s most populous state anticipates hospitals becoming overwhelmed with patients and while it is preparing stadiums and convention centers to handle a crush of cases.

"If you’re a nursing school student, a medical school student, we need you," Gov. Gavin Newsom said. "If you’ve just retired in the last few years, we need you."

Medical professionals are the heroes of this moment.



We need ALL healthcare workers out in the field. This is an all hands on deck situation as we prepare for what’s ahead.



Doctors, nursing students, EMTs & more--CA needs YOU.



Sign up. Spread the word: https://t.co/EfQYLH7nZC — Gavin Newsom (@GavinNewsom) March 30, 2020

Newsom signed an executive order to temporarily expand the health care workforce and allow health care facilities to staff at least an additional 50,000 hospital beds by waiving certain professional licensing and certification requirements to get them in the field faster.

In the last four days, hospitalizations have doubled, and the number of patients in intensive care has tripled, Newsom said.

At midday, the state had more than 6,300 cases and 132 deaths of reported cases, according to a running list by Johns Hopkins University.

Facebook pledged $25 million to help provide childcare and transportation to the new workers, Newsom said.

Those who are eligible were asked to register at the California Health Corps website.

The announcement came as San Francisco and six surrounding counties said they would extend stay-at-home orders until May 1. On Sunday, President Donald Trump, bracing for a national death toll exceeding 100,000, bowed to recommendations from public health experts and extended restrictive social distancing guidelines through April.

Over the weekend, more people appeared to heed the message to stay home after beaches and many parks were closed by state and local officials following a swarm of visitors during the first weekend of the state's stay-at-home order.

Still, people continued to crowd some of the open parks. On Sunday, the state expanded closures amid concerns people were not keeping a proper distance from one another. Parking lots at all state parks were closed, and the most popular places were closed to all activities.

How Coronavirus Has Grown in Each State — in 1 Chart

New York has quickly become the epicenter of the American coronavirus outbreak. This chart shows the cumulative number of cases per state by number of days since the 10th case.

A surfer in Manhattan Beach south of Los Angeles was issued a citation that could carry at $1,000 fine for violating orders to stay off the beach.

To help prepare for a wave of patients, National Guard troops set up beds in the sprawling Los Angeles Convention Center, converting it from a site that normally hosts meetings, trade shows and exhibitions into a field hospital.

The U.S. Navy hospital ship Mercy received its first patients Sunday after docking at the Port of Los Angeles, where it is intended to ease pressure on hospitals by taking in people with non-COVID-19 ailments.

Testing among the state's 40 million residents has stepped up significantly after a slow start. But Newsom said there was a frustrating lag in getting tests results quickly.

San Francisco's subway and light rail system closed Monday, with service replaced by buses. Rail ridership had dropped by more than 90%.

For most people, the coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death.