CANadian Weather Amateur Radio Network

The CanWarn program is a severe weather spotting and reporting program organized and run by the Meteorological Services Division of Environment Canada.

CanWarn is the eyes and ears of Environment Canada. It exists in Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick and Nova Scotia and is a program similar to that of SkyWarn in the United States.

Ontario has approximately 1,800 spotters who are of all ages and come from all walks of life. As much as 30% of the severe weather events Ontario experiences each season are reported by CanWarn spotters.

Since these volunteers are distributed throughout our communities, they are able to contribute valuable information to Environment Canada. Their reports offer “ground-truth” information, which when used in conjunction with radars and other equipment, allow Environment Canada to more accurately inform the media and public through Environment Canada issued and updated Weather Watches and Warnings.

This invaluable service, which started as a joint program with HAM radio operators and Environment Canada, helps protect members of the community as well as those in the areas where the storms are headed.

CanWarn volunteers are active during the thunderstorm season from April to October. On occasion, the type of storm systems with which CanWarn spotters help may occur as late as November.

CanWarn does not operate during the winter months because the type of “ground-truthing” aid they are able to provide Environment Canada during does not generally occur during winter storms.

CanWarn does not operate after nightfall. Only during daylight hours are spotters able to actually see any important weather related developments and events which are of value to Environment Canada.

How CanWarn got started

The program was established in 1987 after the Edmonton Tornado at the request of the Hage Report and put into full service the following year. Within a week after the Hage Report, over 120 amateur radio operators in the Windsor, Ontario area were trained and another 100 in Edmonton, Alberta.

Organized storm spotting in Canada had existed prior to CanWarn but operated independently of Environment Canada, never fully achieving the success that the CanWarn program did. Initially, CanWarn was predominately based in southern Ontario and central Alberta but eventually grew to encompass the entire country by the early 1990's.

How a CanWarn Net works

CanWarn is organised into local networks. When there is the potential for threatening weather, Environment Canada will send a page out to the CanWarn Net Controllers with a directive to start the CanWarn Net. At that time, most Amateur Radio CanWarn volunteers are already aware of the threat and have tuned into their local CanWarn Net operating frequencies.

The Net Controller will open the Net, taking check-ins from the volunteer CanWarn Amateur Radio operators. This initial phase establishes who is around and available to spot for this particular storm. When CanWarn members spot severe weather, they use their Ham radios to call in their reports to the CanWarn Network Controller, who in turn determines what is a reportable event and then sends in the report to Environment Canada's severe weather office in Toronto.

At the weather office, the severe weather meteorologist combines the data from the satellites and radar with the information from the ground, to refine the forecast or prepare a Severe Weather Watch or Warning.