Snow. That's one of the Rideau Canal Skateway's biggest enemies, especially if it falls early in winter.

Snow forms an insulating layer on the canal that prevents ice from forming. And it's impossible to use heavy equipment to clear it away.

As it stands, it takes 10 days of -10 C weather to make the canal safe for skaters. Not all parts of the canal develop the same ice thickness at the same time. There's a bit of a "heat island" effect downtown, for example.

A Carleton University research team believes that lightweight robotic snow-clearing devices could be used on the canal in December, when the average temperature is about -6C.