Thank you @SophatCHY for this post.
I had the same idea 7 years ago: Mapping in emergency areas
At that time Crisis alert was not implemented yet.
Now Crisis-related alert in Google Maps should activate automatically if you are in an area that’s at risk.
@JordanBurleson wrote a post recently about this topic: Navigate To Safety: Your Guide to Using Google Maps During a Flood . I think you will find it interesting
For more official sources: