By Emily Turner

SONOMA COUNTY (KPIX 5) — Learning from failures in last year’s Wine Country wildfires, Sonoma County recently tested a new wireless emergency alert system, but it got mixed results.

The test alert, which was meant to only go out to residents of Sonoma County, was actually sent out much further.

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People in five specific locations in the county were supposed to receive the alert on their cell phones whether they’d signed up or not. The results were mixed, especially in Guerneville.

Sonoma County emergency alert map (CBS)

“Unfortunately, what I have to share today is that I’m hearing from my constituents that they did not actually receive the cellphone notification,” said Sonoma County Supervisor Lynda Hopkins.

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There was also significant spillover; people outside the specifically-targeted areas received an alert when they shouldn’t have.

A survey showed that people in Sea Ranch and Vacaville–and even as far away as Japan–received an alert. Officials said the problem may take federal regulation to fix, but the process may be complicated.

“Each of the carriers has their own cell phone sites located in different areas around the target area. They have different ways of determining which cell phone sites to turn on. Those algorithms, the systems, the processes they use are not clear to us,” said Chris Godley, the Interim Emergency Services Manager of Sonoma County.

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The FCC has a mandate in place for November 2019 that says wireless carriers have to be able to pinpoint an emergency alert message within 1/10th of a mile of where a government official says it needs to go.