Following last week's tornado in New Brunswick, Environment Canada is telling people they need to take cover when it issues a tornado warning.

Bob Robichaud, a meteorologist with Environment Canada, told CBC News that new technology is making it easier to detect severe thunderstorms and tornadoes in the Maritimes.

"We don't actually see the tornado on our radar, but we do detect the motion," said Robichaud.

"The Doppler radar … sees how that precipitation is moving within a storm itself. So we can detect when there's actual rotation in a particular thunderstorm."

Robichaud said the Doppler radar can help predict a tornado about 30 minutes in advance, and people should react quickly if they hear a warning.

"Tornado warnings are not quite like your heavy snowfall warning in the wintertime, where we can give you about a day or two advance warning," he said.

"Tornado warnings are as soon as you hear one, you have to take cover immediately because it means there is something out there."

A tornado hit the small community of Glassville, about 40 kilometres south of Perth Andover on July 2. Environment Canada said the storm was an F1 tornado, with winds of at least 116 kilometres an hour.

No one was injured, but trees were uprooted, buildings were smashed and woodlands were flattened by the storm.

Tornadoes aren't as common in the Maritimes as in some other parts of the country.

Environment Canada says the regions that get the most tornadoes, the "tornado alleys," are southern Ontario, Alberta, southeastern Quebec, and a band stretching from southern Saskatchewan and Manitoba through to Thunder Bay.

Western New Brunswick is considered a tornado zone, Environment Canada says, as is the British Columbia Interior.