The Insurance Bureau of Canada says the June flood in southern Alberta is the costliest natural disaster in Canadian history.

The bureau says the latest estimate of the insured property damage now exceeds $1.7 billion.

Bill Adams, vice-president of IBC's western and Pacific regions, says in a release that the number is staggering and is expected to rise.

Four people died and 100,000 others were forced from their homes by days of torrential rain, prompting states of emergency in Calgary and several other communities.

Property Claim Services Canada, which tracks losses arising from catastrophic events in the country, says well over 25,000 claims have currently been filed in the flood's aftermath.

Federal Public Safety Minister Steven Blaney said last Tuesday that Alberta may soon get an initial interim payment of $500 million from Ottawa to help cover flood costs.

Climate change is making weather patterns unpredictable and that's led to a string of losses for the insurance industry, says Don Forgeron, president of the Insurance Bureau of Canada.

This year's flood is "the costliest in history and it comes after a long string of costly years in Alberta and across the country. We are averaging over the last four years almost $1 billion a year in claims for natural catastrophes. That number doesn’t account for everyday run-of-the-mill claims," he said in an interview with CBC's Lang & O'Leary Exchange.

He said any solution to the problem had to go beyond raising premiums and applauded Premier Redford for measures to control land use in flood plains and deny anyone who builds there insurance coverage.

Communities across Canada have got to address how they develop land, he added.

"Everyone wants to live by the river, until the river starts flowing through your basement as we’ve seen in those photos out of Calgary." said Forgeron. "Governments are now starting to pay attention."