Well, I don't think there's any point arguing anymore that it's winter. The snow has come and gone a few times already in Ottawa, and it's only a matter of time before it's cold enough to stay on the ground. And while I love Ottawa winters for all the great outdoor stuff there is to do, sprinting on slippery streets really sucks. And while there are indoor gyms and inflatable domes around for the flush of pocket, what is a poor hobo to do? Well, my advice is turn to the transit tunnels, young man.
This city has a bunch of them - overpasses for pedestrians to cross over the busy streets in order to transfer to another bus. Here's the one I use at Blair Station:
It's a nice long stretch of wide, covered cement walkway - my guess is about 100 metres end to end - that has the distinct advantage of being bone dry all winter long. It's open 24 hours a day and free to use, provided you don't accidentally plow into any old ladies carrying their groceries back from the shopping mall or a pack of smartphone zombies on their way to catch the next big red limo. I wouldn't recommend it at rush hour, but later in the evening (after 8pm or so, when I have time to run anyway) is almost abandoned. Weekends aren't bad either. You run into (well, not literally) the odd person, but it's never an issue.
It has the nice advantage of having a gentle, arching slope to it too, so it's excellent to do uphill and downhill work if you want. Another great aspect is the ceiling, which has all exposed metal rafters, which are perfect for pull-ups:
One of my favourite 'tunnel' workouts is to alternate end-to-end sprints with a set of pull-ups on one end and a set of toes-to-bar on the other end, rinse and repeat as many times as possible.
Whether it's a blizzardy night outside or a freezing January afternoon, with sun streaming in through the windows, it's a great place to run. It's one of the things I love about winter, and I always miss the transit tunnel a bit once the weather gets nice in the spring.
Just another great benefit of public transit - free, year-round fitness for the people!