Wireless devices, radio and TV stations will issue emergency alert messages Wednesday.
The signals from provincial and territorial emergency management systems across the country, except in Nunavut, will be transmitted to test the national public alert system.
The alerts are intended to warn of imminent threats or emergencies, such as floods, tornadoes, fires or Amber Alerts.
The emergency alerts as part of the national public alert system was first tested in early 2018, revealing glitches in several provinces.
According to the Canadian Radio-television and Telecommunications Commission, 125 emergency messages have been issued since January, warning Canadians of potentially life-threatening situations.
Pelmorex Corp., which operates the system's technical infrastructure, says the tests are necessary to ensure the system is working properly and to educate Canadians on what the warning signals look and sound like.
To receive alerts, compatible wireless devices must be equipped with the latest operating software. They must also be connected to an LTE network when the alert is issued.
The test alert in Ontario will be issued at 2:55pm.
— with files from The Canadian Press