Packed Down snow is just as slippery as ice.
Also, underneath that 15 cm layer of snow, is ... ice. Dude, don't try to act like 3 cm is ANYTHING like 15 cm. I remember last year, we got a solid 2 feet here in Strathroy, Ontario.
Ah, good times.
Also, there are hills in Edmonton. Even then, 3 cm doesn't make a big difference on a hill. Seriously, it doesn't.
Also, do you have winter tires? That might be why its hard to get around.. Either way, stop trying to pretend 3 cm is as much as a detriment as Vancouver.