Where we live we have to really only watch for forest fires. Since there is only one way in and out of town, two highways south after 30ish kms. Still only one way north...and that end in a dirt road that is pretty much impassable. If a fire were to block the highway south again we would head north, there are places to stay out there if we had too. If they fear the highway will be crossed, or the fire will reach the city they give enough notice to evacuate, which we would. They also offer flights out for those who don't have the ability to drive out. We have a shadow population of about 50,000 people living in camps around here, few of them have transportation.
Because of the natural lay out of the community if there is a fire close to the north side of the city they evacuate to my area, as is marked, if the fire is on the south side of the city we evacuate to their side, as marked. They are also in the event of flooding, but we are way to high up for that to be a concern to us.
These big freaking rivers are what the city has been built around. The biggest one is the athabasca river. If curious the area at the very top that you can barely see is where I live.