Are police allowed to arrest, even shoot you for your own safety?
The entire underlying premise for govt forcing you from your home in a disaster is "for your safety". The same for not letting you back in, until they say it is safe.
There is a simple solution (although likely difficult to enact), and that is to simply legislate an act that states that individuals are free to remain in their homes, or return to them anytime they desire, BUT if they do so they, and they alone are responsible for their safety. They may not take any legal action against any govt agency for any harm that befalls them.
Many people will glady choose to face the risks. They may be burned in a forest fire, or drowned in a flood, but if it is their choice, why not let them?
The drawback to this idea is someone who does suffer harm, and later claims that they wanted out (or in), and the govt ignored them, and is trying to get around its responsibility by claiming that they stayed by their own choice. There is potential for abuse. Perhaps a waiver form could be used. Govts love forms.
I have never felt that any govt official, police or otherwise should have the ability to force you off your home "for your own good" because of a natural (or manmade) disaster. If you choose to stay, you should be allowed to stay. Kind of like "death with dignity", and who knows, you might even survive.
Anytime I see something like this, I am reminded of Harry Truman. Not the President, but the determined old man who lived in a nice cabin on the shore of Spirit Lake, in the shadow of Mt. St. Helens. They warned him. They told him. They did everything they could to get him to leave, but he wouldn't. And because the mountain wasn't clearly erupting dangerously, they couldn't legally force him off. He was happy where he was. Then one day in 1980, Spirit Lake ceased to exist. And so did he. But it was his choice, and I believe he was happy with it. Why not respect that?