Siren-equipped system in San Diego County will alert public to evacuation orders and more

A sheriff's deputy activates the Hi-Lo siren during a demonstration May 4.
A sheriff’s deputy activates the Hi-Lo siren during a demonstration May 4.
(David Hernandez / The San Diego Union-Tribune)

The Hi-Lo system in law enforcement vehicles will be used during emergencies such as wildfires, earthquakes, gas leaks and chemical spills.


A new siren-equipped system in police and sheriff’s vehicles will alert communities across San Diego County to evacuation orders during wildfires and other emergencies, law enforcement and fire officials announced last week.

When activated, the Hi-Lo system blares looping high- and low-pitched sounds — similar to sirens in Europe — and broadcasts evacuation orders in English and Spanish.

“Our message is very simple: When you hear the Hi-Lo, it is time to go,” sheriff’s Cmdr. Ricardo Lopez said during a news conference.

A new siren-equipped system in sheriff’s and police vehicles across San Diego County will alert communities to evacuation orders during emergencies. (San Diego County Sheriff’s Department Media Relations Office)

San Diego Assistant Police Chief Terence Charlot said the Hi-Lo “means you are in danger and you must evacuate immediately.”

The news conference was held to educate the public about the new system so community members don’t panic or become confused when they hear the Hi-Lo sirens and announcements, Lopez said.

He said the system will be used during evacuation orders prompted by wildfires, earthquakes, bomb threats, gas leaks, SWAT standoffs, chemical spills and other emergencies.

The system was recently installed in Sheriff’s Department and San Diego Police Department patrol vehicles. Other police departments countywide will follow suit, Lopez said. Officials said federal grants will cover the costs.

Some departments will need new equipment to install Hi-Lo, but patrol fleets in the San Diego Police Department already are equipped with control panels that allow for a relatively easy software upgrade, officials said.

Agencies already use other methods to alert the public about emergency situations, including social media, reverse 911 calls and text messaging. Deputies and officers also go door to door to evacuate residents during emergencies.

“[The Hi-Lo siren] means you are in danger and you must evacuate immediately.”

— San Diego Assistant Police Chief Terence Charlot

“Hi-Lo alerts entire neighborhoods they are in immediate danger,” the Sheriff’s Department said in a statement. “Our goal is to reach as many people as possible with emergency instructions even when phone lines are not working or there are no internet or mobile networks available.”

Charlot said the 2017 wildfires that ravaged Northern California, including Sonoma and Napa counties, made first responders realize a need for a new method to evacuate communities, especially when there’s no time for officers or deputies to knock on doors.

San Diego County has seen many large wildfires in recent years, including the Witch Creek and Guejito fires in 2007, which killed two people and destroyed more than 1,500 buildings in northern San Diego and inland North County, and the Lilac fire in 2017, which tore through Bonsall, destroying 157 structures and killing more than 45 horses.

In September 2020, a new state law allowed for law enforcement vehicles to be equipped with Hi-Lo to alert the public to evacuation orders.

“When seconds count, Hi-Lo can save lives,” said Criss Brainard, chief of San Miguel Fire & Rescue and vice president of the San Diego County Fire Chiefs Association. ◆