A United Nations evaluation team will go in within 24 hours to assess the damage and the needs of those still living in Kosovo, and to pave the way for the eventual return of 800,000 refugees, the first of whom may be going home in two weeks.
"We are expecting this to be one of the most challenging operations we have ever seen," said Paula Ghedini, spokeswoman for the UN High Commissioner for Refugees.
She is also optimistic: "We are fairly certain the vast majority of refugees will be back way before winter."
The aid workers' priority will be to help the thousands camped in the open in Kosovo, and in makeshift shelters thrown together on mountain tops and in ravines, hillsides and woods.
No one is clear on the number, but tens of thousands, perhaps hundreds of thousands, of people, including children, the sick and the elderly, are believed to be living rough.
Although some Kosovars want to return home immediately, the UNHCR believes the bulk will have to remain in the hot, crowded refugee camps until the UN and the Kosovo peace implementation force (K-For) can guarantee a safe environment.
Ms Ghedini said thousands had already been forced out of their homes in Kosovo two or three or four times. "They want to make sure everything is set on the ground and they can go back," she said.
The UN children's agency Unicef has launched an information campaign warning refugees of the hazards they face back home, including mines, booby traps and unexploded ordnance.
For its part, UNHCR plans to publicise descriptions of the conditions back home as soon as possible.
"We expect there will be spontaneous returns," said Ms Ghedini - people "who want to go back and see first, before their whole family returns".
She said the agency would not try to put obstacles in the way of voluntary returners. "We want to make sure we can be present first and have assistance available to them."
To ease what could well be an arduous, traumatic journey, the UN will set up transit centres providing food, blankets, plastic sheeting, wooden frames and tents, so that those with ruined houses can pitch camp close to home and make rudimentary repairs.
If the withdrawal of Serb forces and the deployment of K-For goes as planned, the first organised refugee returns could take place within two weeks, Ms Ghedini said.
The first areas cleared for resettlement would be around Pristina and some other large towns. Checking villages, many of them connected only by dirt roads, will take longer.
Because of the threat of mines, UNHCR is determined to channel Kosovars along main roads that have been judged secure by K-For. Since most of the 250,000 refugees living in Macedonia were expelled by bus and train, their return journeys can be organised and controlled by UNHCR. But Ms Ghedini fears that the operation will be more difficult for the 440,000 refugees in Albania, many of whom arrived in the country by tractor or on foot.