HI-LO

What Is Hi-Lo?

Hi-Lo is a sound you may hear when you must evacuate immediately. This warning system is different from the sirens you hear regularly when deputies, paramedics, and firefighters respond to emergency calls.

Hi-Lo is a very distinct tone that alternates between a fixed high and low frequency sound. It quickly alerts neighborhoods that they may be in immediate danger.

Use of Hi-Lo

The San Diego County Sheriff’s Office only uses the Hi-Lo during natural disasters, extreme emergencies, or critical incidents that require the evacuation of a specific area.

Hear the Hi-Lo

When you hear the Hi-Lo, it is time to go. If you are in an evacuation area, leave immediately and follow directions from law enforcement or emergency personnel.

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When Hi-Lo May Be Used

The Hi-Lo may be used during incidents that require people in a specific area to leave quickly for their safety.

Wildfires
Earthquakes
Flash floods
Tsunamis
Sinkholes
Bomb threats
SWAT standoffs
Terrorism
Hazmat incidents
Gas leaks

What To Do If You Hear the Hi-Lo

Leave the area immediately if instructed to evacuate.
Follow directions from deputies, firefighters, and other emergency personnel.
Pay attention to official emergency alerts and updates.
Do not delay if your neighborhood is in danger.

Why the Hi-Lo Matters

The Hi-Lo is designed to quickly alert people in a neighborhood that there may be an immediate threat. Because it is different from the sirens used by emergency vehicles responding to calls, it helps signal that the public may need to take action right away.