What is the difference between a
weather watch and a warning?
Storm season is rolling in, which means the news will be dominated
with weather advisories, watches and warnings. While all these terms
cover exceptional weather events, they differ in meaning and severity.
It is the responsibility of Environment and Climate Change Canada to
issue Advisories, Watches and Warnings.
Advisories
Advisories and weather
statements can be used to
cover a wide array of
deteriorating weather
conditions and are frequently
used to describe weather
events that can be cause for
public concern.
Advisories and weather
statements can be issued
before watches and warnings
or they can be issued to indicate
severe weather in a
long-term forecast.
Watches
Watches are issued when
there is the potential for
severe weather.
When conditions indicate
severe weather is forming, a
watch will be released to
make the public aware of
what could happen.
Warnings
A warning is the next step
in the process.
Warnings are issued
when that severe weather
is actually occurring or is
imminent.
For example, a tornado watch would
mean there is a good chance that a
tornado will form in the affected area,
whereas a tornado warning would
mean a tornado is occurring or about
to occur and those in the region
should take cover immediately.
Identifying Watches and Warnings
Tornado Watches occur when conditions
favorable for a severe thunderstorm with a
tornado are imminent.
Tornado Warnings occur when a tornado
has been reported or there is evidence a
tornado is imminent.
Severe Thunderstorm Watch is issued if there is
the potential for the development of a
thunderstorm with either wind gusts of 90
kilometres an hour or greater, hail with a diameter
of two centimetres or greater, or heavy rainfall
(with 50 millimetres or more within one hour).
Severe Thunderstorm Warning would be issued if
a cell was spotted on radar with one or more of the
weather conditions listed above occurring.
london.ca/emergency
Helpful applications in emergency
preparedness
Alert Ready – Canada’s Emergency Alert System
!
Alert Ready is a nationwide emergency alert system issued by authorized
government agencies designed to inform Canadians about emergency
concerns in their areas with an alert sent to your phone by text, television or
radio. Wireless providers have also collaborated with the government to allow
text messages to be sent to mobile devices across Canada, provided that they
are connected to a 4G network. Alerts will go out for Tornado warnings, severe
thunderstorms with winds over 130km/hr, and hail bigger than 7cm.
Test messages may be sent to your device to ensure that the Alert Ready
system is up and running. You can learn about the test schedule in your area
through the Alert Ready website.
If you recieve a notification you should take shelter immediately.
Alert London
The City of London has implemented an emergency mass notification
system to alert Londoners during a community-wide emergency. This
notification system allows the City greater efficiency in helping to distribute
timely information and instructions exactly where they are needed. In the
event of a large scale emergency, Alert London will provide critical public
safety messages. The system is designed to reach you at your preferred point
of contact (text or voice), using the information you use to register online.
WeatherCAN
Receive weather alert notifications in your area, as well as in your saved
locations, wherever you are in Canada. Get your latest forecast
information directly from Canada’s official weather source
Check Environment Canada’s website for forecasts, radar, warnings, and links to
other weather related information at weather.gc.ca
For more tips on emergency preparedness:
london.ca/emergency
ontario.ca/emo
GetPrepared.ca
