As an easy first reference to handle tomorrow, below is a link to the Alberta Employment Standards Code Fact Sheet on Family Responsibility Leave. Essentially every employee who has 90 days service with you is entitled to up to 5 days family responsibility leave. For this to apply the child must be of an age that child care is required and the parent / employee must have reasonably explored all options. So for tomorrow could both parents stay home and claim this leave? No normally should just be one and only if there are no other reasonable child care options (which understandably may be the case for many tomorrow). Clearly we are all going to have to work together for the next few days here while we all figure out the "new normal" and do our part to "flatten the curve".
Employers should also check their own in house policies and / or collective agreements as many provide for a limited number of these days to be paid.
Finally, a more advanced point on which legal advice should be sought, but you should also be mindful of family status accomodation obligations under Human Rights.
Personal and family responsibility leave Eligible employees can take up to 5 days of leave for health issues or family needs.