"We have access to all parts of the county, and we're partners with all the surrounding counties," he added. "We can directly contact our counterparts and advise them of the threat so they can get out messages as well."
Central to the effort is the San Mateo County Alert system, which sends emergency messages to registered cellphones, tablets, email accounts and landline phones.
"Users can customize their alerts to their neighborhoods depending on the message so we don't disrupt the city for something that only affects two streets," Norris said. "But if a gasoline tank truck accident shuts down (Highway) 101 the entire length of the county, we would send (the alert) to everybody."
Subscribers are receiving an average of one routine message a day, but a major incident can trigger six or seven messages, he said.
"I receive all of the messages myself but if I was just getting the ones directed to the community where I live, I would not have received one for a couple of months," Norris said.
The service is free to anyone who works or lives in the county. People can sign up at smcalert.info.
Slightly more than 11% of the county's 760,000 residents have signed up for the service, including about 50% of Portola Valley and Woodside residents, Norris said.
"Residents with a high wildland interface are especially concerned about early warning," he said. "They also know who their neighbors are, which can also help spread the word."
The county is also connected to the National Weather Service's radio, which can transmit messages about non-weather-related local emergencies to people who own weather radios.
A weather radio receives weather forecasts from National Oceanic and Atmospheric Administration radio stations that can also carry alerts about natural disasters, terrorist attacks and other emergencies.
"You can get a weather radio for as low as $20, with $60 being the high end," Norris said.
A third system available is known as Reverse 911, which comes with every landline phone account.
The system automatically calls all landline numbers near a location where an emergency is occurring, Norris said.
"It's very rare that you get such a call," Norris said. "We've had maybe five or six so far this year."
The slowest method of alerting people is through social media sites, which rely on people intentionally going to them and reading the messages, Norris said.
SMC alerts and the National Weather Service radio alerts fall under the umbrella of IPAWS, the federal Integrated Public Alert and Warning System. IPAWS gathers alerts over a network and distributes them to the correct systems for broadcast to the public.
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