Top ten weather stories for 2011: story three

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3. Richelieu Flooding…Quebec’s Longest-Lived Disaster

A map of Canada indicating the location of the flooding in Richelieu.

For several weeks in spring, Quebecers living up and down the Richelieu River filled sandbags, sloshed through hip-deep waters and prayed that the flooding would soon recede.  The Richelieu flood was arguably the worst overland flooding in southern Quebec since Confederation and Quebec’s worst natural disaster since the Saguenay flood in 1996. Without question, it was the province’s slowest natural disaster ever – wearing out residents physically and mentally.

© Environment Canada.  Houses and streets flooded along Richelieu River in Quebec, spring of 2011.

Flood conditions started months before in the mountains of northern Vermont and New York. Storm after storm swept over the Adirondacks and Green Mountains around Lake Champlain, leaving a record snow pack. In spring – much later and swifter than normal – the snow started melting, swelling countless rivers and streams that empty into Lake Champlain. Additionally, days of intense rains saturated the ground of headwaters around the Lake, raising water levels to record highs for 37 days in a row. The overflow spilled into Mississquoi Bay, flooding shoreline homes and rushed down the Richelieu River, washing over its river banks and flooding hundreds of farms. In at least 20 municipalities, sloshing waters inundated rows of streets up to a kilometre from the river’s banks. But water didn’t just drain into the Richelieu; southerly winds also pushed metre-high waves into the river from Lake Champlain. With overpowering force, water surged north at volumes as much as five times greater than the Richelieu’s average year-round flow.

© Environment Canada.  Houses and streets flooded along Richelieu River in Quebec, spring of 2011.

Just when the threat seemed to be easing, flooding worsened in the last week of May. Following several wet days from an almost immobile weather system, more rain and strong winds caused water levels on the Richelieu River to rise yet again to an all-time high of 30.7 metres. Hundreds of roads and bridges were heavily damaged, parts of the shoreline were swept away and thousands of hectares of farmland were submerged. Fish swam where grain should have been growing. Canadian Forces personnel -- about 800 strong -- and patrols from the Sûreté du Québec were mobilized to help weary townsfolk and local emergency officials. Relentless spring rains and the incredible slowness of the declining water levels prolonged the agony for 2,000 stressed and demoralized residents, who were kept from returning home for weeks.

© Environment Canada.  Flooding along Lake Champlain near Philipsburg, Quebec spring of 2011.

Spring rains were unprecedented all around the Richelieu. Montreal had its wettest March to May on record in 2011 – 182 per cent of normal. Southeast of Montreal, the rainfall numbers were even more dramatic. At Lennoxville, there were nine days in May with rain amounts exceeding 10 mm (normal is 3.4). When homeowners around the Richelieu did return, it was to ruined belongings, thick mould, building rot, cracked foundations and overflowing septic tanks. Flooded farmland became non-cultivable and schools closed for lengthy periods, forcing students to transfer. In July, an army of volunteers 10,000 strong moved into the area to clean up what the receding waters left behind. SOS Richelieu was the largest volunteer-led cleanup operation in the province’s history. After weeks after backbreaking labour and heartbreaking losses (in excess of $78 million), water-logged residents of the Richelieu Valley were finally able to move on with their lives but the psychological toll and memories will last forever.

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