MAPUTO, Mozambique — The fierce winds and torrential rains slammed into three of the poorest countries on earth, upending the lives of more than one million people in a matter of minutes.

Then the floods from Cyclone Idai came and stayed.

Nearly a week after southern Africa was hit by one of the worst natural disasters in decades, it was all rescue workers could do to try to reach the victims, let alone count them.

People were clinging to trees, desperately waiting for some form of rescue. Around them, the remnants of homes sat in piles, collapsed as easily as if they had been houses of cards. Hundreds of thousands of people in Mozambique alone were displaced.

And everywhere there was a vast inland sea where once there had been land.

“This is now a water operation,” a fellow aid worker told Matthew Cochrane, a spokesman for the International Federation of Red Cross and Red Crescent Societies.