- How would you know when to evacuate? In some places, the most common reason to evacuate would be if the police knock on your door and say they are evacuating the neighborhood because of a barricade situation. In other places, annual flooding and wildfires are the most common reasons for announced voluntary or mandatory evacuations. Pay attention to the news, especially if it is "the season" for evacuations like wildfire season, hurricane season, flooding season, etc. Also, it is a good idea to have a NOAA weather radio on hand which will announce such perils heading your way.
- How would you evacuate? Ideally you would be able to pack up your vehicle and leave. Those without cars would probably need to take a community-provided bus (this is common in hurricane-prone areas), get a ride with friends or even strangers, or in a worst-case scenario leave via bicycle or on foot (the worst options IMHO). Hopping on a plane to quickly leave the area is also an idea (an expensive idea, generally, but sometimes the best option depending on the situation).
- Where would you evacuate to? For many people who aren't rolling in cash and don't have friends or family in other areas they can get to, their options may be evacuating to a community shelter. I heard that there were plenty of people evacuating last hurricane season to inland campgrounds which sounds like a less than ideal situation, and lucky folks were taken in by friends or family members out of the mandatory evacuation zone. Ideally you would have enough money for a hotel stay but even that is iffy, if in fact everyone and their brother coming from an evacuation zone has the same idea (in this situation people have to travel further and further away to find hotels with vacancies).
- When would you evacuate? Ideally you would decide to evacuate at the first sign of trouble. This is rarely what people do, however. There are plenty of people who choose to ignore mandatory hurricane evacuation orders, deciding to stay in their homes no matter what. There are plenty of people who will resist evacuating until the last minute because they can't afford to leave/don't think the situation will be as bad as everyone is saying/aren't prepared and have no idea how to actually evacuate/are otherwise hindered from leaving because their car has no gas and all of the gas stations are closed, etc. The average person can choose when to leave but those who are old or ill or, for example, women who are 8.5 months pregnant, should definitely get out of the potential disaster area sooner rather than later. Leaving sooner is also a good idea in potential wildfire areas (these fires travel FAST), and in areas where a million other people will soon be on the road trying to get out of Dodge.
- How would you actually evacuate? Take one vehicle, gather up all the family members and their BOBs (bug out bags), gather all pets and their pet BOBs, if you have stored gasoline at your home or you can siphon it from another of your vehicles, fill up your gas tank (this will get you far out of the area before needing to stop for gas), grab the tubs of camping gear, fill up the rest of the space in the trunk with bottled water and food from the pantry, stop by the safe to pick up vital documents/cash/jewelry/etc. If you have time, leave a note taped--facing out-on the front window with "evacuated on ____. Going to ____. Phone ______". Lock all doors and windows then leave. Turn your vehicles's radio to the local news station to alert you to roads that may be closed, call ahead if you are planning to go to a friend or relative's home, and determine if you may need to take an alternate route out of town. Note that unlike many people featured on the news, you should never be running around your house trying to figure out what clothes to take, trying to determine if you can bring priceless antiques, wondering where the tent is and staring at the pantry to determine if or what kind of or how much food to take...all of these things waste time. Being prepared ahead of time, having your most important things ready to go, even using a quick checklist so you don't forget anything can save minutes which could mean the difference between life and death.
Prepare NOW even if it is very unlikely that you will ever need to evacuate so that in the event of an emergency, you will be packed, in your vehicle, and hitting the road within five minutes of deciding it's time to leave. More info on evacuating here, here, here, and here.