UPDATED: 2:25 p.m. History has shown that the best bet against a flood is moving out before the rains fall. Residents can monitor potentially disastrous rainfall through a host of devices and alert systems — some old and some new.
One device in particular is getting renewed attention for its longstanding but reliable technology.
Emergency preparedness experts at a Coastside Community Emergency Response Team training recently touted a radio that can tune into a network of National Weather Service radio transmitters that continuously stream regional weather information. These gadgets, called NOAA weather radios, have made a comeback after emergencies in recent years proved that cellular-based systems are prone to failure in areas with poor reception.
Finding alternative communication systems became a county focus after concerns about missed alerts surfaced following the CZU Lightning Complex fires, especially in areas like Butano and Gazos Creek, which were hit hard by the fire and now face the threat of post-fire mudslides as winter intensifies.
The NOAA weather radio is part of a larger overhaul that includes the activation of Coastside CERT volunteers as integral to the county’s response during an emergency.
The NOAA weather radios were once in vogue but receded into the background with the advent of the Wireless Emergency Alert, a system established by the federal government that sends text-like messages to mobile devices. San Mateo County relies on this message-based wireless system in emergencies.
But Brian Garcia, warning coordination meteorologist at the National Weather Service, said the NOAA weather radios are making a comeback.
“It really came to light in the 2017 North Bay fires when we lost power and we lost cell towers,” Garcia said of the shortcoming of wireless. “There was no WEA, no (Emergency Alert System), and NOAA weather radio was the last thing standing.”
The city of Santa Rosa acquired more than 1,000 NOAA weather radios soon after the North Bay fires. Four months after the CZU fire in August, San Mateo County is following suit and has purchased 100 NOAA radios. The radios arrived last week and will be made available to qualifying local residents, officials say.
“Thirty dollars for a potential lifesaver,” Garcia said. “So worth it.”
Mike Mckeon, emergency services coordinator at the San Mateo County Office of Emergency Services, said the county is awaiting shipment of radios.
Watch vs. Warning
The key to the NOAA radio program is that they are programmed to pick up frequency from the closest radio station broadcasting regional weather information.
San Mateo County is caught between two possible frequencies, one of which largely covers the southern end of the county. Both coverage areas overlap in some places so Garcia said residents will have to look at the coverage maps of the San Francisco and Monterey Marine stations and decide if one is better for their location. But like all stations nationwide, both convey up-to-date information about rainfall and the threat of mudslides.
In the case of a flash flood risk, the weather service will issue either a “watch” or a “warning.” Whether residents should interpret either alert as a signal to evacuate depends on location.
During a watch, there's significant precipitation and lots of water but no immediate threat of flooding. A warning, on the other hand, is likely issued when there is heavy downpour and should be heeded with greater urgency, said Garcia.
The two alerts have different lead times. A watch arrives anywhere from a few seconds to 45 minutes before rainfall with the potential to cause a flash flood. A warning registers 12 to 24 hours before a flood.
Notably, flash flood watches and warnings are different from evacuation warnings, which are issued by the county. NOAA weather radios do not currently announce evacuations information. However, Garcia said the National Weather Service can include evacuation information in its broadcasts at the county’s request.
County asks CERT to step up
While radios promise a more robust signal range than wireless alerts that come through cell phones, there are still dead zones, particularly in deep valleys that are unreachable even by radio frequency. In these cases, residents must rely on in-person warnings, likely from neighbors and locally stationed CERT volunteers.
“We’re going to engage CERT to help support us in that area, primarily because we’ve identified massive barriers with communication,” said Mckeon. “We’re not going to be able to rely on our cell phone reception so we’re going back to … engaging at a community level.”
In November, the county’s emergency services office created an updated response plan that emphasizes the activation of CERT volunteers in communicating information hours before an emergency. As part of this plan CERT volunteers will also receive additional training and formal recognition as Disaster Service Worker Volunteers, a status that comes with workers’ compensation if injury occurs.
Mckeon said his office is working to engage CERT and hand radios to broadcast some of the messaging that isn’t getting to remote areas.
This version corrects the number of radios ordered by San Mateo County.