From July 18 to 21, 1996 the Saguenay Flood became one of Canada's costliest natural disasters.
The Saguenay River, located in Quebec, drains Lac Saint-Jean in the Laurentian Highlands, leaving at Alma and running east; the city of Saguenay is located on the river. It drains into the Saint Lawrence River. Tadoussac is located on the northeast bank at this site.
The flood was caused by a series of flash floods. Problems started after two weeks of constant rain, which severely engorged soils, rivers and reservoirs.
Over 8 feet of water flooded parts of Chicoutimi and La Baie, completely levelling an entire neighbourhood. More than 16,000 people were evacuated. The official death toll was seven, but other sources cite ten.
Estimates reach CA$1.5 billion in damages, a cost made greater by the disaster's occurrence at the height of the tourist season. 488 homes were destroyed, 1,230 damaged, and 16,000 people evacuated from the entire area. An additional ten persons died in the mudslides produced by the incredible rain.
An unexpected effect of the flood was to cover the heavily contaminated sediments at the bottom of the river with 10 to 50 centimetres of new, relatively clean sediments.
Research has shown that the old sediments are no longer a threat to ecosystems.