The first barges came yesterday at dawn completing an epic 17-day journey along the White Nile to deliver their human cargo from Khartoum to Juba, the capital of what may become Africa's newest country next month.
Washerwomen on the west bank sang a high-pitched welcome to the hundreds of incoming refugees who crowded the decks ululating and beating drums.
The half-dozen rusting hulks that floated into Juba with more than one thousands passengers were the latest additions to a wave of southerners flooding out of the north ahead of a January vote expected to split Sudan in two.
As many as 75,000 southerners have moved south, according to the UN, aboard makeshift convoys of trucks, buses and barges. Some have come to vote and others to escape a feared backlash in the Muslim-dominated north.
"These big numbers are moving earlier than humanitarian agencies had anticipated," said Vincent Bolt from Catholic charity Cafod. "It has not yet reached humanitarian crisis proportions but the UN estimates are that up to 800,000 in the next six months could make the journey, which would be a 10 per cent increase of the southern population."
The influx is coming into one of the poorest countries on earth where nine out of 10 people live in abject poverty. In the would-be new country, a girl has more chance of dying in childbirth than finishing school.
Three weeks today, a referendum in the south will decide whether to divide Africa's largest country under the terms of a 2005 peace deal that ended the continent's longest civil war. An overwhelming "yes" vote is expected in favour of secession.
Prior to the ceasefire, 22 years of fighting between the Arab-ruled north and the predominantly Christian and animist south left two million dead and scattered millions of refugees. As war ravaged the south, emptying vast areas, the population of southerners living in the north swelled to 1.5 million.
A recent drumbeat of threatening noises from the government in Khartoum has persuaded many to abandon their lives in the more developed north and move south.
Elizabeth Eden was on the last of yesterday morning's barges, bearing a banner proclaiming: "First Sea Group Comes Home." Standing on the top deck she responded to the welcome calls from the banks by beating a drum improvised from a water container and leading dozens of women in a celebration dance. The reception offered a glimpse of South Sudan's complex future as the homecoming barges and the bank-side welcome committee called out to each other in foreign languages.
Aboard the boat the returnees sang of being "home free" in fluent Arabic while those on land answered in southern languages of the Dinka, Nuer and Bari.
The 48-year-old school teacher left her house unsold in Khartoum and came with her three daughters, six sons and dozens of grandchildren.
"Those in the north said if we vote to separate we'll get no medicine, we'll get no school. How can we stay there?" she asked. So 30 years after moving north to escape the war her extended family sailed south bringing all the possessions they could carry with them.
"I came to a new country and whatever I find in Juba I will never go back," she said. "I was singing God has broken my chains and now I'm free."
The crowded decks of the incoming vessels resembled floating refugee camps with open stoves mingling with sleeping mats, sacks of onions and mounting rubbish. Despite the squalor many of the new arrivals had donned their finest clothes to meet the new country, the children decked in beads and braids.
By late morning a human chain had formed across more than a dozen barges lashed together at the makeshift river port. In the soaring heat men, women and children heaved their worldly goods onto their heads and carried beds, mattresses, bicycles and suitcases onto the precarious gangplanks to reach the bank.
Simon Freemon got his first sight of his "motherland" arriving with his wife and two children. Frustrated to have missed the deadline to register for the 9 January vote, he was heading straight to the authorities to petition for the right to take part in the ballot.
"I want to add my voice and end the oppression of the last 25 years," he said.
Malis Mami Oman pulled out a family photograph album and begged the crew on the barge to look out for the rest of his family who are waiting back in Khartoum for the next chance to leave.
Rona Peligal, Africa director at Human Rights Watch, said: "Political parties and governing authorities need to reassure the public that they will not expel anyone and will fulfil their duty to protect all minorities within their jurisdiction during and after the referendum."
Large-scale troop movements in the oil-rich states on both sides of the prospective future borders have stoked already high tensions. Leaked US diplomatic cables recently confirmed accusations that authorities in the south have been stockpiling arms ahead of the vote in defiance of an international embargo.
Meanwhile earlier this month the Sudanese military launched bombing raids across the Western Bahr el Ghazal state, near southern Darfur in an apparent violation of the peace deal.
US officials said the attack came at the same time as increased support was being channelled to "militant proxies" from the governments of Sudan and Southern Sudan.
Sudan: A timeline
1898 - 1956 After Lord Kitchener's military campaign, Britain and Egypt administer Sudan jointly, with the British having most say.
1956 Sudan achieves independence, but strife between north and south looms.
1958 A military coup removes the civilian government.
1962 - 1972 Civil war is sparked by the Khartoum administration's refusal to create a federal system of government. A peace accord signed in Ethiopia guarantees partial self-government for the south.
1983-2005 Second civil war ignited by Khartoum's Islamicisation policy. The subsequent peace deal provides for a referendum on independence for the south.
2003 Rebellion in the Darfur region of western Sudan. Khartoum is accused of sponsoring Arabised Janjaweed militia. Many thousands are killed and one million people flee.
2011 Scheduled referendum is expected to back independence for south Sudan.