Authorities in Nigeria, seeking to relieve strain on two local dams, opened the dams’ gates Friday, sending a flood downriver that has displaced two million people. Opening dams after heavy rainfall is a common practice in the country, but rains have been uncommonly strong this year, and reports say that the amount of water that flowed from the dam was unexpectedly large. It is not known whether local residents were informed beforehand about the dam openings. The Associated Press has the full story.