The early arrival of a tropical storm off the U.S. east coast does not mean Eastern Canada should brace for a particularly active hurricane season, Canadian forecasters said Thursday.

Bob Robichaud of the Canadian Hurricane Centre is predicting an average number of hurricanes this year, despite the formation of tropical storm Alberto off South Carolina last weekend.

"If we look back since 1950, there have been 11 times we've seen storms develop in May," Robichaud told a news conference at the centre's headquarters in Dartmouth, N.S.

"In about half those years, the entire season has ended up being near or below normal. So even though we did get a storm early on this season, it's not necessarily an indicator that it will be an overly busy season."

Alberto has been downgraded to post-tropical status and is expected to stay offshore as it moves up the Atlantic coast.

U.S. forecasters with the National Oceanic and Atmospheric Administration released their outlook Thursday for the six-month hurricane season, which begins June 1.

They are predicting between 9 and 15 named storms this year, with one to three expected to become major hurricanes with sustained winds of 178 kilometres per hour.

Forecasters are keeping an eye on hurricane Bud as it churns in the Pacific Ocean. The storm was expected to reach the southwestern coast of Mexico on Friday.

El Nino expected in late fall

In Dartmouth, Robichaud said there are a number of factors that could change the forecast, including the arrival of El Nino in the late fall — a warming of surface ocean temperatures in the eastern Pacific.

"Whenever we have an El Nino, it tends to be a suppressant to hurricane activity," he said.

On average, one or two storms directly affect Canadian territory every year, with another two or three threatening offshore waters.

Residents of the East Coast are well acquainted with warnings to stock up on batteries, flashlights and water as storms approach. But thrill-seekers often can't resist flocking to the coastline to feel the stinging spray from waves pounding rocks.

Last August, the remnants of hurricane Irene smacked Eastern Canada with powerful gusts and torrential rain, flooding roads, snapping trees and knocking down power lines.

Hundreds of thousands of people in Quebec, New Brunswick and Nova Scotia were left without electricity as the post-tropical storm passed through.

But the region emerged relatively unscathed from the sprawling storm, which killed more than 20 people along the Eastern Seaboard in the United States before it weakened. Hundreds of island homes were destroyed when Irene slammed into the Bahamas as a Category 3 hurricane.

Weeks later, hurricane Katia kicked up big waves along the East Coast as it churned in the Atlantic Ocean. The Category 1 storm didn't make landfall.

'Nothing wrong with being overly prepared'

Hurricane Maria pummelled parts of Newfoundland in mid-September with gusts in excess of 100 km/h. The following month, the remnants of hurricane Ophelia took a parting shot at the island, dumping heavy rain and forcing a handful of evacuations when it made landfall on the Avalon Peninsula.

But neither storm packed the same punch as hurricane Igor in September 2011.

Igor was a Category 1 storm with gusts of 140 km/h when it roared through the island, dumping 200 millimetres of rain, causing one fatality and almost $200 million in widespread damage.

The World Meteorological Organization has since removed Irene and Igor from its list of storm names. The name Juan was retired nearly a decade ago after hurricane Juan roared through Halifax and Prince Edward Island, causing $100 million in damage.

The vicious storm was blamed for at least eight deaths in September 2003 and was the worst storm to hit Halifax in more than 100 years.

Steve Mills of Nova Scotia's Emergency Management Office said people shouldn't become complacent despite this year's predictions.

Hurricane Andrew ravaged parts of southern Florida and Louisiana when it struck in 1992 during what was expected to be a light storm season, he said. At least 40 people were killed.

"Because of Andrew alone, it turned out to be one of the most devastating years in hurricane history," said Mills.

"It only takes one Andrew, just as in Nova Scotia in 2003 it only took one Juan. There's nothing wrong with being overly prepared. In our business, the opposite approach can be disastrous."