It's pouring and far above freezing in Quebec in December. Yep, that's weird

Quebecers are used to the occasional December warm spell that dashes hopes of a classic white Christmas, but the massive weather system blanketing the south of the province and Atlantic Canada right now is beyond that.

In Quebec City and surrounding areas, heavy rains have dumped a month's worth of precipitation in less than 24 hours, forcing evacuations and prompting officials in the provincial capital to activate their crisis unit as local rivers swell with rain and melted snow. Water levels along the Montmorency river, which spills into the St. Lawrence just east of Quebec City, could reach 30- or 40-year highs — for the third time in a year.

Simon Legault, a meteorologist with Environment and Climate Change Canada (ECCC), said previous temperature records will be smashed across most of southern Quebec. 

"The temperature records are already broken but [temperatures] will continue to increase during the day," said Legault.

There are flood warnings for a number of regions in Quebec. In Montreal, between 50 and 80 millimetres of rain is expected by Monday evening, with ECCC's warning of local flood risks already a reality in some parts of the city.

"It's very unusual," Legault said of the weather system, which he said has brought warm, humid air from the southern U.S. — a phenomenon far more common in early fall. "We are really settled in winter conditions. We don't receive these kind of systems this time of year."

In Montreal, the temperature hit 9 C at 7 a.m., exceeding the average temperature by 11 C and beating a record that has stood since 1921, according to CBC's Climate Dashboard. Going east, some temperatures are even higher: Rimouski and Sherbrooke hit 14 C this afternoon, Quebec City 10 C, all records.

Some combination of El Niño — which has returned this year and brings warmer, moisture-filled air north to Canada — and general climate change trends could explain this "out-of-the-ordinary" weather, Legault said. Climate change models forecast "warmer air for the time of the year where we should be getting colder temperatures" and "more heavy downpours because the air can hold more moisture," he said.

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As much as 100 millimetres could fall in the Quebec City region by Tuesday morning and 140 millimetres in the Charlevoix region, east of the provincial capital.

Officials declared a state of emergency in Stoneham-et-Tewkesbury, north of Quebec City, warning of a strong chance of floods. Firefighters evacuated 27 homes along the Montmorency river near Beauport, just east of the capital. 

Quebec's Public Security Ministry says the Portneuf, Nelson, St-Charles, des Hurons, du Gouffre, Famine, Chaudière and Etchemin rivers are all under flood watch. Sylvain Gallant, a spokesperson for the ministry, said the volume of rain is "highly unusual" and that the heaviest precipitation is expected Monday night.

The Baie-D'Urfé Rescue Squad was at work Monday morning pumping flooded basements in the West Island community. ECCC has warned that partially frozen ground is less able to absorb rainwater, the levels of which are being added to by melting snow.

Mixed conditions for winter sports

The impact of double-digit positive temperatures and record-breaking rainfall on winter sports depends on the sport and the venue.

Downhill ski resorts have invested heavily in snow-making technology to mitigate the effects of climate change, said Yves Juneau, the head of the Association des stations de ski du Québec (ASSQ), which represents the province's ski mountains — so they're prepared for less favourable weather patterns.

"At the end of the day, with all of our snow-making capacity, we're able to cope with this kind of weather," he said, adding that real challenge for resorts is persuading people that grass in their backyard doesn't mean grass on the slopes.

(Ski areas will need to continue to invest in snowmaking technology, Juneau said, to permit snowmaking at warmer temperatures and more efficient use of water.)

Quebec provincial parks that are typically open this time of year remain open, but the activities available may be reduced said Simon Boivin, a spokesperson for the Société des établissements de plein air du Québec (SEPAQ).

Some ski, hiking and bike trails in some Quebec provincial parks are back to grass because of the rain, Boivin said. He said people should check the status of trails on park websites before visiting.