The second powerful cyclone to rip into Mozambique in just six weeks has stunned residents in a region where such storms had not been recorded in the modern era.
Three deaths were reported from Cyclone Kenneth and the United Nations warned of "massive flooding" ahead.
Kenneth had maximum sustained winds of 220km/h, equal to a Category 4 hurricane, before it made landfall on Thursday evening in far northern Mozambique, the Joint Typhoon Warning Center said.
It was the first time in recorded history that the southern African nation has been hit by two cyclones in one season, the UN said.
More worryingly, the storm's remnants in the next 10 days could dump twice as much rain as Cyclone Idai did on central Mozambique last month, World Food Program spokesman Herve Verhoosel said. Idai killed more than 600 people and displaced scores of thousands.
Kenneth struck a part of Mozambique that had never seen such a fierce storm during the age of satellite observation, forecasters said, renewing concerns about climate change and the country's vulnerable, 2400km Indian Ocean coastline.
While the region that took the brunt of Kenneth is more sparsely populated than the area hit by Idai, Mozambique's disaster management agency said nearly 700,000 people could be at risk, many left exposed and hungry as flood waters rise.
The UN children's agency, on the ground in Macomia, described families taking shelter in a church as Kenneth ripped apart their homes - only to watch as the church's own roof was torn away. Some schools were destroyed, it said.
The largest city in the cyclone-hit region, Pemba, had significant power outages.
"This is a very vulnerable area, higher in poverty" than the one hit by Cyclone Idai, Red Cross spokeswoman Katie Wilkes said.
Before reaching Mozambique, Kenneth hit the Indian Ocean island nation of Comoros, were it flooded 1000 homes and destroyed key crops, Wilkes said.
Australian Associated Press