SAN JOSE — Santa Clara County has had access to technology that could have quickly sent alerts to residents’ mobile phones about the Coyote Creek flood, but few county workers know how to use it and the system has yet to be implemented.

Mobile phone users already receive such automatic notices from the National Weather Service about storm warnings or from police with Amber Alerts about missing children. Most Bay Area counties, including Alameda and Contra Costa, are set up to use what’s called the Integrated Public Alert and Warning System, or IPAWS, for their own emergency notifications.

On the other hand, while Santa Clara County has been authorized to use the system for nearly two years, county officials said they haven’t done so because the county hasn’t developed a policy about how and when to use it, and has yet to retrain employees after a change in vendors.

“It will be part of our new system in place by the end of March, but currently it is not,” said David Flamm, deputy director of the county’s Office of Emergency Services. “The first step is getting people trained on the basics of the new system. The next step will be getting the dispatch center trained on IPAWS.”

It’s unclear to what extent the high-tech alert system — which is administered by FEMA — might have helped in the Feb. 21 San Jose flooding. A key problem in getting word out to residents in harm’s way that morning appeared to be misunderstanding between city and flood control officials about the seriousness of the mounting threat.

For many residents, their first official notice of the flood danger came when rescuers arrived at their door in boats to ferry them to safety, something Mayor Sam Liccardo has called a “failure.” Quick, automated alerts as waters rose might have helped some escape before they needed to be rescued.

Flamm said that the county could “theoretically” activate the alert system now, if needed, and that local agencies — including the city of San Jose — have been informed that’s the case.

But city spokesman David Vossbrink said Wednesday that San Jose didn’t know a wireless warning system could be part of the response.

“It did not come up on our plans and actions as an available resource in all our many conference calls with our partners, including the county,” Vossbrink said.

For nearly a decade, the county has had an AlertSCC system in which residents can opt to be notified of emergencies on their home phones, mobile devices and via email. That system also has the capability of making automated calls to landlines based on geography, popularly known as a “reverse 911 call.”

What makes the IPAWS system, administered by FEMA, different is that it relies on a wireless emergency alert protocol, first used in 2012.

Many cellphone users already are familiar with that system’s “Emergency Alert” notifications, which deliver automated flash-flood warnings triggered by the National Weather Service.

The system automatically targets phones within a danger zone based on their proximity to a cellphone tower, without requiring users to sign up for the warnings. By contrast, the county’s AlertSCC system requires residents to sign up for the alerts.

AlertSCC automatically calls land-line address listings, but more and more people use only mobile phones. County officials have estimated that 40 percent more residents could be reached through the IPAWS system.

Although Santa Clara County is in the heart of high-tech Silicon Valley, it remains among the few Bay Area counties that has yet to get the new alert system up and running.

Contra Costa County sheriff’s spokesman Jimmy Lee said they’ve had the system “for years,” although it is seldom used. Alameda County has had it in place since mid-2015, though it has yet to send out a warning, said Paul Hess of the Alameda County Office of Emergency Services.

The only other two counties in the Bay Area that don’t have the wireless alert system in place are Napa and San Mateo. A San Mateo County sheriff’s spokesman said they have a partnership with the CHP to use their system if needed — and they have, at least twice recently, for an at-risk missing man and a child abduction.

Santa Clara County did not complete certification to use the system until 2015, a year after about half the state’s counties did.

Former San Jose Councilman Pierluigi Oliverio, who sat on the Santa Clara County Emergency Operational Council that moved the technology toward adoption, blamed a “lack of prioritization” on the part of the county for its lack of implementation.

“I believe local government should have a laser-like focus on core deliverables such as public safety,” he said, “and eliminate lengthy discussions on topics such as foreign policy, which is out of the purview of local government.”

Like Santa Clara County, Butte County also didn’t have the new technology in place when it evacuated 200,000 residents last month during the Oroville Dam crisis. Butte emergency services officer Cindi Dunsmoor said the evacuation was handled effectively through other means.

Shasta County recently used the wireless alert system to issue a warning about recent flood threats along the Sacramento River.

Darren Valencia, who lived in San Jose’s Rock Springs during the ‘90s floods but has since moved to Redding, in Shasta County, saw the flooding on the news and felt a horrible sense of deja vu.

“I was there for two floods and never had a warning from the city or anyone,” he said. “Nobody came out to tell us anything. And now, it’s 20 years later and I get alerts here in Redding. Why don’t they get alerts in the high-tech capital of the world?”