The storm fuelled fears of flooding two days it hit the coast, flattened buildings and knocked out communications.
Heavy rains lashed northern Mozambique on Saturday in the wake of Cyclone Kenneth as aid groups warned of possible flooding and mudslides in the days ahead.
At least five people were killed, the government said. Mozambique's disaster authorities said one person was killed in Pemba city and another in hard-hit Macomia district, while residents on Ibo island said two people died there. Details on the fifth death were not immediately available.
Nearly 3,500 homes in parts of northern-most Cabo Delgado province were partially or fully destroyed, with electricity cut and at least one key bridge collapsed.
"The entire area is a scene of vast destruction," Daw Mohamed, humanitarian director with the aid group CARE, said in a statement after assessing Macomia district on Saturday morning. People need shelter, food and water, he said.
Cyclone Kenneth arrived late Thursday, just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people. This was the first time in recorded history that the southern African nation has been hit by two cyclones in one season, again raising concerns about climate change.
Kenneth, packing the power of a Category 4 hurricane, tore into a region that had never seen such a fierce storm during the age of satellite observation. Its remnants could dump twice as much rain as Idai did last month, the UN World Program has said.
Aid groups warned that flooding remained a danger after Kenneth, just as flooding caused most of the deaths after Idai. Some forecasts warned of as much as 250 millimetres (9 inches) of torrential rain, or about a quarter of the average annual rainfall for the region.
The International Federation of Red Cross and Red Crescent Societies reported heavy damage to Cabo Delgado province, with the communities of Macomia, Quissanga and Mocimboa da Praia of highest concern.
Communications remained challenging in some areas as authorities and aid groups scrambled to assess the damage, especially in more far-flung communities in the largely rural region. Mozambique's disaster management agency has said nearly 700,000 people could be at risk, many left exposed and hungry as flood waters rise.
"The situation wasn't worse thanks to awareness-raising work by local authorities," the agency said on Saturday while posting photos of buildings where metal roofs had been crumpled or ripped away.
Other photos from Macomia showed a mud-walled home that had disintegrated, a bus that appeared to have slid off the road and a toppled electrical pole, its wires straining.
People left homeless tried to patch together shelters from the rain.
"I'm looking for someone to lend me a porch so I can clean it up and stay with my family," one Macomia resident, Wild Eusebio, told the Portuguese news agency Lusa.
Another family of 13 people, including eight children, was living in an improvised plastic tent, the report said.