In this photo provided by the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), badly damaged communities are seen from an aerial view, in Macomia district, Mozambique, on Saturday, April 27, 2019. Authorities have urged many residents to seek higher ground in the wake of Cyclone Kenneth as rain lashes the region. (Saviano Abreu/OCHA via AP)
In this photo provided by the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), badly damaged communities are seen from an aerial view, in Macomia district, Mozambique, on Saturday, April 27, 2019. Authorities have urged many residents to seek higher ground in the wake of Cyclone Kenneth as rain lashes the region. (Saviano Abreu/OCHA via AP)
Community members look at rubble and other items washed close to their doorstep when Cyclone Kenneth struck in Pemba city on the northeastern coast of Mozambique, Saturday, April, 27, 2019. Cyclone Kenneth arrived late Thursday, just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people.At least four deaths have been reported in the city and another in hard hit Macomia district, while residents on Ibo Island say two people have died there.(AP Photo/Tsvangirayi Mukwazhi)
Community members look at rubble and other items washed close to their doorstep when Cyclone Kenneth struck in Pemba city on the northeastern coast of Mozambique, Saturday, April, 27, 2019. Cyclone Kenneth arrived late Thursday, just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people.At least four deaths have been reported in the city and another in hard hit Macomia district, while residents on Ibo Island say two people have died there.(AP Photo/Tsvangirayi Mukwazhi)
Men carry a mobile shop to safer ground in Pemba city on the northeastern coast of Mozambique, Saturday, April, 27, 2019. Cyclone Kenneth arrived late Thursday, just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people.Authorities are urging people to move immediately to higher ground as flooding and mudslides are feared in the wake of Cyclone Kenneth .(AP Photo/Tsvangirayi Mukwazhi)
Men carry a mobile shop to safer ground in Pemba city on the northeastern coast of Mozambique, Saturday, April, 27, 2019. Cyclone Kenneth arrived late Thursday, just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people.Authorities are urging people to move immediately to higher ground as flooding and mudslides are feared in the wake of Cyclone Kenneth .(AP Photo/Tsvangirayi Mukwazhi)
In this photo provided by the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), badly damaged communities are seen from an aerial view, Ibo island, Mozambique, on Saturday, April 27, 2019. Authorities have urged many residents to seek higher ground in the wake of Cyclone Kenneth as rain lashes the region. (Saviano Abreu/OCHA via AP)
In this photo provided by the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), badly damaged communities are seen from an aerial view, Ibo island, Mozambique, on Saturday, April 27, 2019. Authorities have urged many residents to seek higher ground in the wake of Cyclone Kenneth as rain lashes the region. (Saviano Abreu/OCHA via AP)
In this photo provided by the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), badly damaged communities are seen from an aerial view, in Macomia district, Mozambique, on Saturday, April 27, 2019. Authorities have urged many residents to seek higher ground in the wake of Cyclone Kenneth as rain lashes the region. (Saviano Abreu/OCHA via AP)
In this photo provided by the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), badly damaged communities are seen from an aerial view, in Macomia district, Mozambique, on Saturday, April 27, 2019. Authorities have urged many residents to seek higher ground in the wake of Cyclone Kenneth as rain lashes the region. (Saviano Abreu/OCHA via AP)
Men repair a road damaged by Cyclone Kenneth in Pemba city on the northeastern coast of Mozambique, Saturday, April, 27, 2019. Cyclone Kenneth arrived late Thursday, just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people.At least four deaths have been reported in the city and another in hard hit Macomia district, while residents on Ibo Island say two people have died there.(AP Photo/Tsvangirayi Mukwazhi)
Men repair a road damaged by Cyclone Kenneth in Pemba city on the northeastern coast of Mozambique, Saturday, April, 27, 2019. Cyclone Kenneth arrived late Thursday, just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people.At least four deaths have been reported in the city and another in hard hit Macomia district, while residents on Ibo Island say two people have died there.(AP Photo/Tsvangirayi Mukwazhi)

PEMBA — Serious flooding began on Sunday in parts of northern Mozambique that were hit by Cyclone Kenneth three days ago, with waters waist-high in areas, after the government urged many people to immediately seek higher ground. Hundreds of thousands of people were at risk.

"We are unfortunately expecting devastating floods," the United Nations humanitarian agency said in a tweet.

Houses began to collapse and at least one rescue team was mobilized in the region's main city, Pemba, U.N. staffers said. They shared videos and photos of the rushing waters swamping homes and cars. Heavy rain was falling and power was out.

Authorities have said at least five people died after the cyclone arrived Thursday evening with the force of a Category 4 hurricane, stunning residents of a region where a cyclone had not been recorded in the modern era. Kenneth came just six weeks after Cyclone Idai ripped into central Mozambique and killed more than 600 people.

The remnants of Kenneth could dump twice as much rain as Idai did, the U.N. World Program has said. It was the flooding after Idai that caused most of the deaths. As much as 250 millimeters (9 inches) of torrential rain, or about a quarter of the average annual rainfall for the region, is forecast over the next few days.

Nearly 700,000 people could be at risk in the largely rural region, many already exposed and hungry. Some rivers in the region have burst their banks in the past, notably in 2000.

With the flooding streets nearly deserted in Pemba, a few braved the pouring rain. One woman held a plastic dish over her head.

"I have never seen such rains in my life, this doesn't happen in Pemba. The storms we sometimes have, but such rains, never," said a 35-year old resident, Michael Fernando.

Aerial photos taken on Saturday showed several coastal communities flattened by the storm in Mozambique's northernmost Cabo Delgado province. "Not a single house is standing anymore," Saviano Abreu, a spokesman with the U.N. humanitarian agency, told reporters after the aerial assessment.

With many houses built of mud, wooden poles and metal roofs destroyed, families have begun wading through rising waters to what they hope are safer areas or huddling under impromptu shelters.

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.

The International Federation of Red Cross and Red Crescent Societies earlier reported heavy damage to Cabo Delgado province, with the communities of Macomia, Quissanga and Mocimboa da Praia of highest concern.

About 3,500 homes in parts of Cabo Delgado were partially or fully destroyed by the cyclone, with some roads blocked and at least one key bridge collapsed. Some schools and health centers were damaged.

Already, livelihoods have been lost and people are wondering how they will cope in a country struggling with one of the world's highest poverty rates.

With notebook and pen in hand, elderly Luis Momade walked near the beach in Pemba on Saturday, taking advantage of a lull in the rains to quantify the damage from the cyclone. The president of the local Paquite Residents Association, his notebook was almost full with names and figures of boats damaged or destroyed.

With unemployment rife and many in coastal areas surviving with fishing and related activities, not going to sea could mean going hungry for days.

Men, women and children foraged in the waters off the littered shore, looking for seashells to sell.

AP