Douglas County in Colorado has introduced Hi-Lo sirens as a new tool for notifying residents about evacuations during emergencies such as wildfires and natural disasters. The Douglas County Sheriff’s Office and the Douglas County Office of Emergency Management announced the deployment, stating that the sirens are intended to provide an extra layer of warning when other communication systems might fail.
The county already uses several emergency notification methods, including opt-in alerts like DougCoAlert, social media, and universal systems such as IPAWS (Integrated Public Alert and Warning System), Wireless Emergency Alerts (WEA), and the Emergency Alert System (EAS). However, these systems depend on cellular networks, radio signals, Wi-Fi connectivity, and commercial power. In certain conditions—such as mountainous areas with limited cell coverage or during events like Public Safety Power Shutoffs—these technologies may not function properly.
Recent major wildfires have shown that digital alert systems can be overwhelmed or rendered useless in fast-moving emergencies. To address this issue, patrol vehicles will now be equipped with Hi-Lo sirens and pre-recorded evacuation messages. The system emits a unique high-low tone followed by a recorded announcement: “A MANDATORY EVACUATION ORDER HAS BEEN ISSUED FOR THIS AREA. PLEASE EVACUATE IMMEDIATELY.” This warning will only be used during extreme situations where immediate evacuation is necessary.
Douglas County Sheriff Darren Weekly said: “This system is designed for worst-case scenarios — fast-moving wildfires, flash floods, major law enforcement incidents, or any critical event where lives are at immediate risk. Our adoption of the Hi-Lo siren and clear, standardized evacuation terminology ensures that when seconds matter, our residents will hear a distinct warning and know exactly what it means. It’s about clarity, speed, and giving our community every possible advantage in an emergency.”
As part of this initiative, Douglas County is also implementing standardized terminology for emergency notifications to align with regional efforts aimed at improving disaster communication:
– Evacuation Order: Immediate threat to life; lawful order to leave immediately.
– Evacuation Warning: Potential threat; those needing more time or with animals should leave now.
– Shelter in Place: Go indoors; secure doors and windows; wait for further instructions.
“These definitions are designed to eliminate ambiguity. Clear language leads to faster action, and faster action saves lives,” said Douglas County OEM Director Mike Alexander.
Hi-Lo sirens are not meant to replace existing tools such as door-to-door notifications or digital alerts but serve as an additional measure if technology fails.
Douglas County Commissioner Abe Laydon stated: “Public safety is never the work of one office or one agency. It is the result of collaboration, coordination, and shared responsibility. Our Sheriff’s Office and OEM teamwork every day to prepare for emergencies long before they happen — planning, training, testing systems, and ensuring that when something does occur, we are ready to respond quickly and effectively.”
The use of Hi-Lo sirens places Douglas County among several agencies along Colorado’s Front Range adopting similar measures to improve public safety response across jurisdictions.
Residents are encouraged to sign up for emergency notifications at dougcoalert.com so they can receive important updates directly. A video demonstration of the Hi-Lo siren system is available online at https://youtu.be/nKFt-jWXAXE.
