The decision to leave or not should have been made within hours of the event. It is kind of like leaving a football game in the last quarter when you realize your team was going to lose. You make the best of a bad situation and beat the traffic.
When a power out event happens, you must find out as much as you can and as fast as you can in order to make a reasonable assessment and come up with a plan A, Plan B and yes a Plan C.
You should have some sort of timeline that has…if this…then that. Example, if it is a terrorist attack in the city large enough to disrupt services and create panic in the streets, then (Do This) If bugging out is right for you, then get out fast. You should have already had a destination planned and supplies to support your family.