Bad weather is preventing helicopters from reaching thousands of villagers marooned by southern Ethiopian floods.

At least 125 people died when the Omo River burst its banks on Sunday. Residents spent Monday night outside as houses in villages were submerged. 

Officials have sent five motorboats to help. A week ago, floods caused more than 250 deaths in eastern Ethiopia.

Flooding often hits low-lying parts of Ethiopia between June and September, when heavy showers fall on dry regions. 

"As the weather is too difficult for helicopters, we were unable to fly," local police commissioner Tsegay Muluneh told AFP news agency. 

"We have dispatched more boats from the area and from the federal government with more personnel, medical teams, swimmers, divers and emergency food," he said. 

Local officials from the United Nations World Food Programme say about 14 villages are affected, with a total population of 6,000 people. 

It is mostly women, children and the elderly who are still trapped, surrounded by flood waters, WFP told BBC News. 

Over the past two years flooding has afflicted several areas of eastern and southern Ethiopia, killing hundreds and displacing hundreds of thousands. 

The flooding of the river and tributaries, which flow into Lake Turkana on Ethiopia's border with Kenya, also destroyed many homes and swept away hundreds of livestock. 

Weather forecasters say heavier than usual rains are expected in the coming weeks across much of Ethiopia. 

Officials have issued a fresh warning for people living near the Awash River, which is some 300 km (190 miles) east of Addis Ababa, and which flooded earlier this month. 

The authorities in Dire Dawa in the east have banned the rebuilding of settlements on the river banks and declared the areas a disaster zone.

There are 256 confirmed deaths from last week's flooding, but some 250 people are still missing and 10,000 were displaced. "The extensive flooding was a cruel blow for already vulnerable people, many of whom have now lost everything, including their families," WFP's acting country representative Ebenezer Ngowi said in a statement.