According to forecasts, over 80% of the village of Ozhulun of more than 1,000 people may be flooded.
A state of emergency was declared in the region, the local administration told ITAR-TASS on Friday.
The heads of villages and towns are on alert. Aircraft fly over the areas to monitor the situation.
More than 200 rescuers are working there.
Eleven localities may be flooded in two districts of more than 16,000 people.
The flood was caused by torrential rains. Rising water from rivers and lakes broke a dam.