From summer to winter in 24 hours - flood risk increasing across metro Montreal region

Water levels in Vaudreuil are on the rise late Sunday afternoon, with minor flooding being reported in areas close to the shore of Lake of Two Mountains. The municipality completed installing pumps over the weekend to help prevent backflow into the stormwater system. (Valley Weather)

A flood watch remains in effect across eastern Ontario and southern Québec, as water levels along the Ottawa River and it's tributaries continue to rise. The station at Sainte-Anne-de-Bellevue was creeping into the moderate flood range, sitting at 23.91 metres late Sunday afternoon. Moderate flood stage at that location is 24 metres. Water from the Lake of Two Mountains is starting to creep over the jetty near the boardwalk.

Flooding has also forced the closure of Chemin de 'Lanse-A-l'Orme from Senneville Road to Tiberlea Trail along the Senneville/Montreal border. Flooding is also creeping onto Ile Mercier, threatening Louis Roch Street.

You can add Vaudreuil/Dorion to the list of municipalities preparing to fight the advancing Lake of Two Mountains. Public works have been installing pumps along Saint Charles in Vaudreuil to help prevent any backflow in the stromwater system. A dike was also installed at the end of Hotel-de-Ville Street as a preventative measure.

The good news at this time is that weekend precipitation proved to be less than forecast, with only 8mm of rain and a trace of snow falling at Trudeau Airport. Lake levels remain well-below those observed in both 2017 and 2019. Late Sunday afternoon, levels were reported as being stable, but they are forecast to rise slowly through Tuesday.

The strong cold front that moved across the Montreal region overnight, dropped the region from summertime warmth on Saturday back to temperatures near the freezing point Sunday morning. Montreal reached 23C (73F) Saturday, with some southwestern Quebec locations pushing 25C (77F). Gusty southwest winds reached close to 70km/h. By Sunday morning, the temperature had plunged to 2C (36F) in Montreal, with light rain mixing with and changing to light snow.

The week ahead looks chilly, but with little in the way of precipitation expected through Friday. Hopefully this will allow rivers to crest across the region and begin lowering.