Heavy rain warning - risk of flooding for Montreal region

Minor flooding is already occurring along the shores of Lake of Two Mountains, including at Parc Esther Blondin in Vaudreuil-Dorion shown above. (Ledy Quintero)

 Rainfall warning in effect for Montreal. Flood watch is at Level 1 Intervention.

Steady rain is falling across southern Quebec early Sunday morning, not what we need at this time. I have measured 5mm here on Ile Perrot since 1AM. The flood risk remains elevated in the Montreal region and along the Ottawa River.

A rainfall warning has been issued for the metro Montreal region, with 25 to 40mm possible through Monday. The rain will only add to the elevated river levels across western Quebec, and especially along the Ottawa River.

The Montreal region, including Senneville on the western tip of the island (shown above), is now at the Intervention 1 level for flooding. Water levels are on the rise, and rain is forecast for much of the upcoming week. (Valley Weather Photo)

Flooding has already been observed in Riguad, spreading down river towards Lake of Two Mountains. Several municipalities including Vaudreuil-Dorion, Pierrefonds, Ile Bizard and Sainte-Anne-de-Bellevue have started sandbagging and installing pumps. Montreal remains at  Intervention Level 1 and has freed-up resources to deal with any potential impacts.

The upcoming week will be critical, with rain forecast both here and upstream across Eastern Ontario. At this time, officials do not believe the flooding will be as bad as 2017 or 2019, when parts of southwestern Quebec were devastated, and transportation routes greatly affected including the closure of the Galipeault Bridge.

As of Sunday morning, water levels were up, but stable across the region. Riguad was in moderate flood stage at 23.95 metres. Terrasse-Vaudreuil remained in minor flood stage at 23.76 metres, as did Pointe-Calumet at 23.85 metres. All gauges were up from early last week.

The forecast calls for water levels to remain elevated, with minor flooding for the week ahead. That may change if the heavy rainfall develops. The weather for the week looks unsettled and cool, with frequent showers.