FEMA 1% annual chance (100yr return period) floodplain map covers so large area, especially along the open coast and riverine area. If the houses are located within flood zones, the property owners are required to purchase the flood insurance. Yes, many many many houses are in the flood zones. In addition, there are different flood hazard zones, such as V, A, X zones. Also, the base flood elevation is an important hazard factor. So, the flood risks are different depending on the specific flood zones.
https://www.reddit.com/r/Damnthatsinteresting/comments/1fsizno/asheville_is_over_2000_feet_above_sea_level_and/
就是在下图中红圈，属于100年一遇的洪水区
FEMA的洪水地图很早就有了吧，买房子建房子之前都要查一下看看是不是在洪水区
但是我同意flood zone就不应该建房。
也有可能建房的时候不是flood zone，后来因为气候变化，变成flood zone了。
我以前也发过帖子问，为什么有人买在河边的房子，还被嘲笑。。。
最近看了一个房子，在flood zone里，去年刚交易过一次。当时正是抢房疯狂的时候，买家还是加钱买的。今年拿出来卖，但是没有人买。
Yes, many many many houses are in the flood zones.
In addition, there are different flood hazard zones, such as V, A, X zones. Also, the base flood elevation is an important hazard factor. So, the flood risks are different depending on the specific flood zones.