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 reached moderate flood range, Monday, sitting at 24.00 metres. Water from the Lake of Two Mountains has starting creeping 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 has also occurred on 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 Saturday night, dropped temperatures from summertime warmth on Saturday back to 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. Monday morning was even colder, with 0C (32F) at Trudeau Airport.

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.

Metro Montreal region under a Level 3 Flood Watch

Water levels along the Ottawa River on Ile Perrot are on the rise Thursday afternoon, in response to a wet April to date, as well recent ice and snowmelt across the region. A flood watch remains in effect for Montreal. (Valley Weather Photo)

"We have just come up to Level 3, which is the highest level of emergency the city can bring it up to" Montreal Mayor Soraya Martinez Ferrada.

A Level 3 Flood Watch is now in effect for Montreal - allowing for the mobilization of personnel, material and resources in the event of flooding.

Municipalities across the Island of Montreal, Laval and up and down the Ottawa River Valley are in flood watch, as waters levels continue to rise. Many parts of eastern Ontario and southwestern Quebec have had a very wet spring to date, with rainfall closing in on 75mm at Trudeau Airport since April 1. At this time the St. Lawrence River and Lac St. Louis are stable and below flood stage.

Municipalities like Senneville and Sainte-Anne-de-Bellevue on the western tip of the island are in flood watch mode as water levels continue to rise along Lake of Two Mountains. Pierrefonds as well as parts of Laval are also watching water levels rise. (Valley Weather Photo)

The gauges on Lake of Two Mountains at Sainte-Anne-de-Bellevue and Terasse Vaudreuil are at 23.50 metres, or about 200mm (8 inches) above minor flood stage. Water levels have stabilized at both locations for today but are expected to rise slowly in the coming days in response to higher water levels upstream. Pointe Calumet is at 23.58 metres and rising. Minor flooding has been observed.

Montreal and the Burroughs will be monitoring the levels 24/7 at the cities emergency operations centre for the near term, ready to provide assistance as needed.

As far as the forecast goes, the city remains under a special weather statement for the potential of more heavy showers through Sunday. Rainfall amounts of 15-25mm are possible. The good news is that Saturday looks dry now, and cooler, drier weather next week may slow down runoff and water levels.

Across the province, 12 rivers are in minor flood stage, while 17 more are on the rise, and being monitored. Vigilance will be important over the next week as water levels fluctuate. At this time, we are not expecting to reach the record levels and subsequent flooding that occurred in both 2017 and 2019.

A strong cold front will push across southern Quebec on Saturday night accompanied by showers and maybe even a rumble of thunder. Sunday looks much colder, with temperatures falling from highs in the low 20s (70F) Saturday, down to 5C (41F) Sunday. Montreal will likely drop below freezing into Monday morning, -3C (27F), and I can't rule out a stray snowflake or two.

April showers bring May flowers...and spring flooding

Rainfall over the last 72 hours has dropped 30 to 35mm across southern Quebec. The rain along with melting snow and ice has resulted in sharp rises in area rivers. Several are approaching minor flood stage. Vigilance is important over the next few weeks, especially if you live along or near  flood prone areas of southern Quebec. More rain is forecast over the next three days in Montreal.

It is that time of the year again where we hold our breath as rapid snowmelt and spring rain swell our rivers. During the past two weeks across our region, most of the ice has melted away from both the Ottawa and Saint Lawrence Rivers as well as the tributaries in and around southern Quebec. This combined with rainfall this April has resulted in sharp rises in the rivers that surround our island as well as Laval.

Since April 1st, 72.4mm of rain has fallen at Trudeau Airport. Rain has fallen on 12 of the 14 days this month, with more forecast over the next 72 hours. Sécurité Publique Québec has been monitoring the gauges around southern Quebec and reports one in medium flood stage, 7 at minor stage and 18 under surveillance.

Parts of the Mille Îles River are reporting minor flooding, while the gauge in Lake of Two Mountains at Sainte-Anne-de-Bellevue is reading 23.28 metres, just below minor flood stage. Most rivers are slowly rising, with the next 72 hours being critical as to where we go from here. North of Montreal, the Ouareau River near Rawdon is in moderate flood stage.

A wavy stationary front stretching from Iowa to Maine, has been the focus of rain and strong thunderstorms at times. The front lies southwest of Montreal, keeping very warm and humid air just to our south. Most of the storms have been firing up along and south of the front in southwestern Ontario and New England. The front is separating summer from spring, with Windsor, Ontario reaching 27C (81F) on Tuesday afternoon, while Montreal struggled to reach 9C (49F). As I write this blog, Montreal is siting at 7C (45F), while New York City is currently 28C (83F).

Several areas of low pressure will ride along the front producing more showers and thunderstorms through Sunday, with another 15-25mm of rain possible. A cold front will sweep across the region late Sunday, ushering in unseasonably cold air for a day or two. There may even be some flurries around.

Residents across the metro Montreal region who live in flood prone areas adjacent to our rivers, should continue to monitor water levels and listen to information supplied by your burrough or municipality.

Has spring finally sprung in Montreal?

Barring any surprises, Wednesdays snowfall of 1-2cm should be the last of the winter season here in Montreal. (Valley Weather Photo)

Montreal managed a breezy, warm high of 16C (61F) at Trudeau Airport on Thursday, with the mercury inching past 20C for some southwestern Quebec locations. I must admit, it felt good. The final traces of snow have melted away and the cleanup of our fair city has begun.

What could be the final snow of the season, barring any big surprises, put down a centimetre or two on Wednesday. That melted away quickly, but it was enough to create some areas of black ice and several serious collisions. One incident closed the Ville Marie Tunnel eastbound while yet another snarled the Mercier Bridge. You are reminded that despite the warmer weather, we often dip to or below the freezing pint at night in April, so treat any standing water like ice.

In terms of the future, we are looking at a cold front approaching southern Quebec on Friday, with rain expected ahead and along the front. As much as 10-20mm is possible. Temperatures are mild Friday morning, but will dip as the day moves along. Some wet snow may mix in well north of the city and across the Ottawa Valley.

The weekend looks like typical early April weather, with fair skies and highs in the low teens. Another front will bring rain to the region Monday. Next week looks warmer and wet. We may see significant amounts of rainfall over the next week or so.

Looking back at March, Montreal (Trudeau) received 33cm of snow and 45.9mm of rain, including lots of freezing rain. Winter 25/26 has hopefully drawn to a close, with the seasonal total for snow sitting at 213.6cm (84.1 inches).

Another surge of cold air across southern Quebec

Despite the colder-than-normal weather and the occasional snowflakes, the annual spring cleanup is underway in Montreal. Hundreds of city workers are stripping away the layers of dirt and debris left behind by the melting snow. (Valley Weather Photo)

After a highly variable weekend in the weather department, we are looking at another surge of cold air to start the work week. The easter weekend featured both winter and spring seasons at times. We even managed some early morning thunderstorms on Friday, with between 20-25mm of rain falling over the weekend between early Friday and Sunday morning. Despite the rain and clouds Friday, temperatures still managed to reach 15C to 18C (60-65F) across southern Quebec.

A strong cold front late Sunday has brought cold temperatures and even some flurries for Monday morning. Temperatures will struggle today to reach 3C or 4C (35-40F) under clouds, gusty northwest winds up to 50km/h at times and the occasional snow shower.

It has certainly been a cold start to Spring 2026 in Montreal, but it could be worse. On April 3 and 4, 1975, a fierce snowstorm dumped between 30 and 50cm of heavy wet snow on southern Quebec, driven by 100km/h winds. I remember it well, with a two day holiday from school as a result of the late season storm. (La Presse Archives)

A frontal trough will rotate though the region late overnight into Tuesday morning, with another round of light snow or flurries likely. A centimetre or two is possible in the most persistent snow showers. Cold air will remain in place through Tuesday, with daytime highs only near the freezing point and overnight lows tumbling to -7C (19F). Some slightly milder air should arrive by Thursday, with the return of sunshine. Highs will back close to normal, or slightly above near 10C to 13C (50-55F).

Briefly taking a look beyond this week, there is no real warm air in sight, with temperatures remaining either side of 10C (50F) and overnight lows close to the freezing point. As expected, spring is off to a very slow start in 2026.

Rainy, icy week ahead for southern Quebec

Despite Monday's hint of spring across the Montreal region, we are looking at the risk of more wintry weather in the form freezing rain on Tuesday. 

Special Weather Statement issued for Montreal, southern and western Quebec as well as eastern Ontario and the Ottawa Valley for a messy mix of rain and freezing rain Tuesday.

Spring weather is really at a premium across Southern Québec this March, and with April set to start, there is really no change in sight. A series of low pressure systems will guarantee a wet and at times white or icy mix this week. For Montreal, Monday will be spectacular. Southwest winds will deliver milder air, with a very springlike high of 14C (56F) forecast. That is the good news. The bad news is the warmth lasts a day. 

Arctic high pressure well north of Montreal, will begin to bleed cold air south into the valley locations overnight, as winds veer to the northeast. Temperatures will fall quickly, as a frontal boundary lifts northward to lie close to the international border. Warm air overriding the cold air at the surface will result in a decent swath of precipitation. Depending on where you are in regards to the boundary, that will be either liquid or frozen.

Temperatures across southern Quebec and eastern Ontario will be a degree or two either side of the freezing point on Tuesday, with winds gusting to 50lm/h. In Montreal, I think we will have a messy mix of precipitation, with limited impacts on roads, primarily icing elevated surfaces. Precipitation amounts could be significant, with 20-40mm by Wednesday morning. Most of that should be in the form of plain rain. There is even the chance for a rumble of thunder Tuesday afternoon.

The weather pattern remains the same into Easter weekend, with several more low pressure systems producing widespread precipitation. The thermal boundary will remain tight, with mixed precipitation north of the front and rain along and south. Stay up to date on future forecasts as this is a changeable scenario, with plenty of moving parts.

Another ride on the temperature roller coaster for Montreal and southern Quebec

Salt trucks were out and about once again on Thursday morning, as yet another in a series of clipper systems brought snow and freezing rain to the Montreal region. (Valley weather Photo)

Thursday's low pressure and frontal boundary resulted in more mixed precipitation than originally expected and less rainfall, as temperatures were very slow to warm here in the St. Lawrence Valley. Out high was 3C (38F), well-below the advertised 10C. Such is often the case when a northeast wind is blowing in Montreal.

As far as precipitation goes, we managed another 3-4cm of snow early followed by a couple of hours of freezing rain and eventually rain. The liquid precipitation amounted to 7mm at Trudeau Airport. Roads were a little slippery for the morning commute, but otherwise the impacts were minimal as the storm system was rather weak.

Temperatures fell rather quickly overnight into Friday morning, as a cold front slipped south of the region. The temperature fell from 2C (36F) at 1am, down to the current reading of -7C (19F). Add to that a gusty northwest wind of  40km/h and windchills are in the middle minus teens, way too cold for late March!

In what many hope was the last snowfall of the season, Thursdays weak storm system brought 3 to 5cm of fresh snow to the Montreal region. The monthly total at Trudeau Airport stands at 33cm, with a seasonal total of 212.8cm (83.8 inches) to date from November 1st to March 26th. (Valley Weather Photo)

Our region remains of the northern edge of a large dome of high pressure that has resulted in scores of record temperatures established across the central and southern United States. Phoenix has had eight consecutive days of 100F (37C) plus temperatures. Prior to 2026, they had only had one such day in March. The heat has pushed all the way north into the Ohio Valley, but remains just south of our region.

Southern Quebec remains below normal for late March, along with weak low pressure, one after another bringing us light amounts of precipitation. The end result has been a rather cool, damp month, with 38.9mm of rain and 33cm of snow.

I wish I could say the first week of April will be different, but the trend looks the same. After a cold weekend, we can expect temperatures to be on the rise Monday into Tuesday, with more shower activity. We may see highs as warm as 15C (59F) by Monday. Unfortunately, that will be followed by another cold front, more northeast winds, flurries and a high of only 2C (36F) on Tuesday. 

There is some indication that this pattern may finally break by the second week of April, with more substantial and longer lasting warmth settling into Montreal. Time will tell, but for now the pattern remains the same, the temperature roller coaster ride nobody wants to be on.