In a statement on 10 November the UN Office for the Coordination of Humanitarian Affairs (OCHA) said the funding sought would be used to provide food, water and sanitation, health and nutrition services, shelter, protection and education.
According to OCHA, 3,264 houses were totally destroyed or damaged beyond repair, and 20,000-25,000 people were made homeless in Hadramaut Governorate.
"The timeline for the humanitarian assistance will range from two to six months, with the food assistance expected to extend until the next harvest in April 2009," the statement said.
Thousands of hectares of agricultural land, as well as roads and bridges, were destroyed by the floods. State-run media said the World Bank estimated the damage at US$1 billion.
Ahmed al-Haddad, head of Economic Development, a government body in Mukalla, said infrastructural facilities - electricity, water, telecommunications and roads - had been affected.
"The disaster was bigger than could be imagined," he told IRIN, adding that the damage would hinder achievement of the Millennium Development Goals, and that Mukalla District had been particularly hard hit.
Ramadan Aboud, head of the Planning Ministry's office in Seyoun, said a 2006-2015 development strategy for Hadramaut Valley's 16 districts may now have to be revised.
"The floods have damaged the infrastructure, and this has now placed restrictions on our ambitious targets," he told IRIN.
According to Aboud, the authorities should "study and analyse the reasons for the havoc caused in Hadramaut. and also take into consideration climate change." Reconstruction would require local and foreign funds, he added.