Prime Minister Justin Trudeau says officials at all levels of government must develop a plan to "rebuild better" as Canada braces for more frequent floods and fires related to climate change.

Trudeau spoke to reporters Thursday morning after touring the Gatineau, Que., flood zones by helicopter with Premier Philippe Couillard.

Trudeau said a "tremendous" cleanup is ahead as the water levels recede.

Going forward, officials must also develop a rebuilding strategy that makes communities more resistant and resilient to extreme weather events.

"We're going to have to understand that bracing for a 100-year storm is maybe going to happen every 10 years now, or every few years," he said. "And that means as we look to rebuild our communities, our homes, our infrastructure, we're going to have to think about what we can do to rebuild better."

PM Justin Trudeau says the frequency of extreme weather means we need to think about how we rebuild communities. 1:20

Asked if municipalities should be allowed to build in areas known to be at high risk of flooding, Trudeau said officials must consider a plan in a "thoughtful and measured" way.

Trudeau praised the collective response to massive flooding in Quebec and other parts of the country, noting that volunteers, neighbours, first responders and military personnel are doing an "extraordinary job."

'Canadians come together'

"We can really see that Canadians come together and unite in difficult times," he said.

About 2,200 Canadian Armed Forces personnel have been deployed to assist in relief efforts, and the Canadian Red Cross has launched an appeal for donations to help residents rebuild their homes and lives.

The federal government has contributed $1 million to that appeal, and Trudeau urged all Canadians to donate generously to the fund.

On Wednesday, Public Safety Minister Ralph Goodale called the flooding a "large-scale disaster."