In case your default US time will probably run out if you are in Canada, and you should return to your US immediate from Canada, you'll want to submit an application for a US visa with an extended time frame (eg B-one/B-two, or possibly a C-1 transit visa) in advance https://canadian-news04791.prublogger.com/36999344/an-unbiased-view-of-canada-breaking-news