Emergency alerts mistakenly go off in California county warning people to 'prepare for action'

SAN LUIS OBISPO, Calif. – Residents of California’s San Luis Obispo County received a series of unsettling erroneous emergency alerts as repairs were being made to a nuclear power plant’s siren system.

Emergency services manager Ron Alsop says a siren at the Diablo Canyon nuclear plant began wailing Friday afternoon for no apparent reason. Crews had upgraded the siren earlier in the day as part of a revamp of the emergency system.

County officials issued an alert message indicating there was no emergency, but that unknowingly sent a vague alert to cellphones in the area with a special tone and a message that there was a “civil emergency” and people should “prepare for action.”

When county officials realized the gaffe, they issued a final message stating that there was no cause for alarm.