More than 10,400 homes across Russia have been flooded, the RIA state news agency reported.The most serious situation is in the Ural Mountains, the agency said.The Ural River, which rises in the Ural Mountains and flows into the Caspian Sea, swelled several metres in just hours on Friday due to melt water, bursting through a dam embankment in the city of Orsk, 1,800km (1,100 miles) east of Moscow.