In 1997, Environment Canada announced a $34.9 million, seven-year plan to establish a national Doppler weather radar network. The network will improve public safety by giving meteorologists the data needed to detect and predict severe weather more quickly and more precisely.

Using data from Doppler weather radar, meteorologists will be able to provide more accurate information more quickly about where a storm will hit and the amount of snow or rain the area is likely to receive. In the event of a storm with heavy rains predicted, this information could be invaluable to organizations such as municipalities and conservation authorities in charge of flood control or the management of combined sewer overflow and storm water run-off in cities and towns. Similarly in the winter, information on the place, time and amount of snow predicted could help municipal and provincial road crews with their snow-clearing operations.

Severe weather such as blizzards, freezing rain, strong winds, hail, tornadoes, and heavy snow and rain exact a heavy toll in lives and property damage. For example, in Canada, poor weather conditions cause on average 220 fatal car accidents and more than 11,500 severe injuries each year. Since Doppler weather radar will help meteorologists detect severe weather sooner, they will be able to issue weather warnings at an earlier stage in the storms' development. This would give Canadians more time to protect their families and property.

The New Doppler Weather Radar Network

Over the seven years of the project, Environment Canada is buying 11 new Doppler weather radars and retrofitting 19 existing weather radars with a Doppler capacity. By 2003, there will be 31 Doppler weather radars across the country from Vancouver, British Columbia to Holyrood, near St. John's, Newfoundland. Data from the Canadian Doppler weather radar network and the U.S. Doppler weather radar network is being exchanged.

The Doppler weather radars have an effective range of 250 kilometers in radius. The full network will cover those areas which are particularly prone to severe weather and protect 90 per cent of the country's population.

The area covered by the network was determined first, by the probability of severe weather such as tornadoes, blizzards, hail, and heavy rain and second, by population density. The new sites for the individual Doppler weather radars were determined in part by the location of the gaps in areas covered by the present Canadian and U.S. Doppler weather radar networks.

Conventional weather radars are able to detect the intensity and location of precipitation such as rain, snow or freezing rain. Doppler weather radars do this and also measure the motion of the precipitation within the storms. Using sophisticated computer techniques, meteorologists can derive other valuable information about the motion of the air currents within the storms.

Meteorologists then search the wind and precipitation patterns for the characteristic signatures of different types of severe weather such as strong squalls, down bursts, severe thunderstorms and tornadoes. With this information and other data from satellites, computer models, weather observations and volunteer observers, the meteorologist issues severe weather warnings. These warnings are carried on Environment Canada's Weatheradio service, Web and Automatic Telephoning Answering Devices and; are provided to television and radio stations.