MOSCOW — Torrential rains dropped nearly a foot of water on a Black Sea region in southern Russia overnight, causing intense flooding that killed at least 78 people and forced some in the largely rural area to take refuge in trees and on roofs, officials said Saturday.

Muddy water coursed through streets and homes in the Krasnodar region, in some cases high enough to flow over the hoods of cars.

About 5,000 residences were flooded, the Krasnodar governor was quoted as telling the Interfax news agency.

Igor Zhelyabin, a spokesman for the Krasnodar’s Emergencies Ministry, said 67 of the deaths were in the area of the hard-hit town of Krimsk, about 750 miles south of Moscow. Many people were asleep when the flooding hit, and scrambled to safety.

State news agency RIA Novosti said five people died of electrical shock in the Black Sea coastal city of Gelendzhik after a transformer fell into the water.

As of 10 a.m. Saturday, more than 11 inches of rain had fallen in Gelendzhik since the previous evening.

Gelendzhik is on the Black Sea coast, and along with the area around it, is a popular summer vacation spot, including many children’s camps. Some 7,100 children were at holiday camps in the area, and that with 459 children had to be evacuated.