Montreal could get almost a month's worth of rain on Friday: Environment Canada

Less than a month after Hurricane Beryl brought record-breaking rain to Montreal, the city is expected to get another major downpour at the end of the week, according to Environment and Climate Change Canada (ECCC).

The weather agency is tracking Tropical Storm Debby as it makes its way to Ontario and Southern Quebec and merges with a low-pressure system over the Great Lakes.

During a briefing on Thursday, officials told reporters that the rain will start to fall in Montreal late this evening before it picks up on Friday.

Meteorologist Michèle Fleury said Montreal could receive more than half a month's worth of rain in a 24-hour period, beginning early Friday morning. The average rainfall for Montreal in August is 94 millimetres.

Environment and Climate Change Canada says rainfall amounts could reach up to 80 millimetres in Montreal due to remnants of Tropical Storm Debby. (Source: Environment and Climate Change Canada)

The latest models are forecasting the city could get between 60 and 80 millimetres by Saturday morning.

Areas north of the St. Lawrence River — including the Outaouais, the Laurentians, Lanaudière, Mauricie and Nord-du-Québec — could get even more rain, with amounts possibly exceeding 100 millimetres, the officials said.

Flash flooding and sewer backups are among the main concerns once the storm hits. 

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Officials say people should consider delaying plans and to be mindful during their commutes when the rain is the heaviest.

People stand in front of a house damaged after a tree fell on top of it in Avon Lake, Ohio, Tuesday, Aug. 6, 2024. (Joshua Gunter/Cleveland.com via AP)

Significant rainfall events have been abundant in eastern Canada so far this year and meteorologist Jennifer Smith said, "This reduces the ability to absorb further high amounts of rain due to saturated soils and high water levels."

On July 10, Montreal destroyed a rainfall record when 66 millimetres of rain fell as remnants of Hurricane Beryl barreled through the region. The previous record for that day was 32.5 millimetres in 1945.

According to Nathan Gillett, an Environment Canada research scientist, climate change is making these kinds of severe weather events more frequent.

"We know that in general across North America we have seen an increase in the most intense rainfall events. This is consistent with our understanding of climate change. As the atmosphere gets warmer, it can hold more moisture," Gillett said. "On the global scale, we are seeing an intensification of the heaviest precipitation events and that intensification is expected to increase in the future."

The Associated Press reported that at least seven people died due to Tropical Storm Debby in the U.S., five of them in traffic collisions or from fallen trees. The storm also caused damaging tornadoes that killed one person, flooded a town, and closed down part of Interstate 95 on Thursday in North Carolina.