The parent comment is likely referring to Highway 17, which is the only road connection between Manitoba and Ontario. A boulder once fell on this highway leading to its closure for a period of time.
I've seen this incident be the subject of hyperbolic clickbait articles and YouTube videos discussing the complete cutting off of East and West Canada (conveniently ignoring the realities articulated by your comment). Perhaps the parent comment is vaguely aware of incidents like this and is extrapolating to unfounded conclusions?
https://www.ctvnews.ca/winnipeg/article/how-crews-cleared-a-...
I've seen this incident be the subject of hyperbolic clickbait articles and YouTube videos discussing the complete cutting off of East and West Canada (conveniently ignoring the realities articulated by your comment). Perhaps the parent comment is vaguely aware of incidents like this and is extrapolating to unfounded conclusions?