Walking alone at night is never a good idea, especially for women. If staying with a group is not an option, make sure to remain in lit areas and take safe modes of transportation (car or taxi).
Winnipeg has some incredible bars, but certain bars are known for hosting patrons who get a little out of control. People like to come to dive bars to have more than a few drinks, and the amount of alcohol consumed can lead to rowdiness and potentially violence. Many of these bars are in the North End, but you can find them all over.