By the size and damage it inflicts, small, large, outstanding and catastrophic floods are distinguished.
A small flood causes minor material damage and almost does not violate the normal course of life of people. Repeatability of them approximately once in 5 - 8 years and they are typical for small rivers.
A large flood is accompanied by considerable material damage, including damage to the population. Part of the population, material values ​​and livestock are evacuated. Repeatability - approximately 1 time in 10 - 25 years.
An outstanding flood covers a large river system, almost completely paralyzes the economic activity of the region and causes great material and moral damage. There is a need for mass evacuation of the population. Repeatability of such floods is approximately 1 time in 50 - 100 years.
Catastrophic floods spread to several large river basins. It permanently paralyzes the economic activity of man. Accompanied by human casualties. Repeatability - 1 time in 100 - 200 years and less often.