Sudan has declared a three-month state of emergency on Saturday after flooding killed 99 people this year.
The Sudanese minister of labour and social development said the floods had affected more than half a million people and had damaged more than 100,000 homes.
The flooding was triggered by heavy seasonal rains, mainly in neighbouring Ethiopia. AThe Nile River has risen to nearly 17.5 metres (about 57ft)m the highest level in 100 years, according to the authorities.
On Sudan's Tuti Island, where the Blue and White Nile meet, the highest river waters since records began have left locals trying to hold back the floods.
Residents are filling bags with sand and small stones to try and stop the waters, which has washed away thousands of homes.
"Three days ago the water invaded my house around midnight," said Swakin Ahmad.
"We were knee-deep in it. My husband and I, with our five children, fled... carrying a few things in our hands."
Every year during the rainy season the river floods, and the people of the island expect the waters to rise.
But this year has seen waters rising to record levels.
Heavy rains forecast
Government civil defence officials say that seasonal floods have killed 94 people, injured 46 and destroyed or damaged over 60,000 homes across Sudan during the current season.
But many fear the worst is yet to come.
Heavy rains are forecast to continue through September, both in Sudan and upstream in neighbouring Ethiopia, the source of the Blue Nile.
"Young people tried to rescue things from my house," Ahmad said. "But it was hopeless, because they had water up to their necks and could not see anything."
Residents have set up homemade barrages to block the water, but their efforts have been engulfed by the rising river.
The army has been sent in to help them.
Iqbal Mohamed Abbas, who welcomed many of those forced from their homes at her educational centre, described "the courage with which young people tried with simple means to slow down the flood."
"I am proud of these young people who came to try to stop the Nile with their bodies," Abbas said.
Sudan's water ministry predicts that this year's flood is larger than that of 1998, which destroyed tens of thousands of homes in several states and displaced more than a million people.
The United Nations Office for the Coordination of Humanitarian Affairs (OCHA) estimates that over 380,000 people have already been affected across the country.