Where is the best place to park USD?

Hey Guys,

My Mom has a decent amount saved up in USD. However we are both living in Canada, where would be the best place to have it parked for the short-term, at least in terms of a savings account.

Currently it is in a RBC USD 'high' interest savings account - which has 0.150% interest, which is tiny.

Is it possible to open an account in a US bank as a Canadian - assuming they have better savings accounts - or what other options are there?