Outdoor Warning Sirens

An Outdoor Warning Siren (OWS) system consists of a siren(s) designed to alert people of approaching or existing hazardous conditions, which will require immediate protective actions in order to save lives. Traditionally, these systems have been mistakenly referred to as “tornado sirens” but the term fails to acknowledge all applications for activating sirens. In order to avoid any confusion as to the purpose of these systems, the City of Lancaster shall refer to sirens as “Outdoor Warning Sirens” in an effort to reinforce the multiple conditions for which the City of Lancaster may activate sirens to alert people in outdoor areas.

Reasons for Activation

The City of Lancaster may use Outdoor Warning Sirens to alert and notify people in outdoor areas of emergency situations. Although the typical use of these systems has been to notify people of potentially dangerous weather conditions, there are several reasons why public safety personnel could activate outdoor warning siren systems. Some of these reasons include:

• Severe Weather capable of producing effects that are hazardous to persons or property 

• Local Warning Point (the Northern Ellis Emergency Dispatch) activities in coordination with the National Emergency Alert System 

• Hazardous materials released into the atmosphere 

• Catastrophic emergencies that pose an immediate threat to safety (i.e. dam failure) 

Photo of Warning Siren