MONTREAL -- It's the first sunny day of spring and the surf's up in downtown Montreal.
Downtown, you say, in Canada's second-biggest city, hundreds of kilometres from the nearest ocean?
Yes, downtown, where the detritus of urban life bobs with the current of the St. Lawrence River, forcing surfers to dash out of danger as they slash "the Wave."
It's not exactly the pristine blue water of Maui, but a small-but-avid group of surfers use a massive standing wave in the St. Lawrence to pioneer a new way to "hang 10."
"If you can believe it, I moved to Montreal for the wave," says surfer dude Corran Addison, a native of Durban, South Africa. "Well, the wave and the women, but mainly the wave."
The wave is a murky green swirl in the shadow of the landmark Habitat '67 apartment building, a jumbled stack of building blocks just above the entrance to the Port of Montreal.
It is about 30 metres across and swoops down about 10 metres in front, creating a rotating water flow that combines with gravity to mimic a stationary ocean wave.
On a Saturday in early spring, three local surfers take turns riding the wave while dodging detached blue dock pontoons and a big chunk of wood with a child's balloons tied to it.
The denizens of Habitat sit on their balconies, sipping drinks and watching the show below.
"I'm not sure I would drink the water. Actually, let me rephrase that. I often do drink the water, I don't mean to, but I do," said Mr. Addison, 38, the owner of a Montreal surf shop.
He first used the wave for practice a decade ago as a competitive kayaker passing through Montreal, and discovered he could surf it, too.
Surfers now use standing waves in British Columbia, the Ottawa River in Ontario and Sturgeon Falls in Manitoba.
Mr. Addison spent a recent sunny afternoon in Chambly, Que., on the Richelieu River, where high springtime water and dangerous rapids make an "experts-only" ride.
In Alberta, surfers created an association last year to push Calgary authorities to consider their sport as they planned to build "play waves" in the Bow River.
The Albertans go year round, making -20 winter excursions to the fast flow of the Kananaskis River. They worry about freezing to death instead of choking on sewage.
"Surfing in January can be an amazing and surreal experience," said Paul Barrett, one of the local pioneers.
"Most days, it's just another day on the water. But other days, you have snow coming down, two-foot chunks of ice peppering you, wind, and the ever-lingering threat of hypothermia.
"But you won't see any other river users, just you, your mates, ice and Alberta's Rockies."
Mr. Barrett, 26, grew up surfing in California before moving to Calgary, where he adapted his sport to local rivers with the help of fellow Calgarian Ben Murphy and Montrealer Jean-Louis St-Arnaud.
"River surfing in Canada was definitely pioneered in Montreal," said Mr. Barrett, crediting Mr. Addison and Mr. St-Arnaud.
Andreanne Dumas learned the sport from Mr. Addison a few years ago in Montreal. She's hit the ocean a few times since then. "Personally, I'm better on the river, so I like it a bit better," Ms. Dumas said.
"It's a sport like any other. We take advantage of the water, we take advantage of the sun. And we're so far from the ocean, it's the only way."
Ms. Dumas said there are more similarities than differences between river and ocean surfing, but river waves roll onto themselves like surfing treadmills, allowing long rides to refine techniques.
"The difference is the approach to the wave," she said. "On the sea, you wait for the wave to come to you. On the river, you go to the wave. ..."
Compared to the 10-second rides a rookie ocean surfer can expect, a river surfer can ride as long as their legs can hold.
In an attempt to prove the point, Mr. Addison said he set a record last year when he surfed the Montreal wave for 90 minutes straight.