I guess that would be dependent on what is an emergency for you. Most of us consider the use of a cellphone for personal emergencies when we are away from home. To expect it to remain available in all instances of natural disasters is unrealistic.
Depending on the length of outage, Telus may offer some compensation, but the Terms and Conditions of cellular service state clearly that the service is subject to interruption for a variety of reasons. In any case, any compensation will not be anything close to immediate.