Hundreds of residents were evacuated on Friday as strong winds complicated efforts to control the blaze, which spread across 14,000 hectares (35,000 acres) in the area some 1,500 kilometers (930 miles) east of the capital, Moscow.
"The fire was spreading at a speed of more than 150 meters (490 feet) per minute - that's a huge speed. It was a firestorm, a burst that was impossible to put out," the country's deputy emergencies minister, Ilya Denisov, was quoted as saying by the TASS news agency.
At least 18 people needed medical assistance and one 78-year-old man who refused to leave his home with other evacuated villagers was later found dead, Russian news agencies reported. Nearly 50 houses were destroyed.
Denisov said firefighters had eventually managed to get most of the blazes under control and contain them.
An Ilyushin IL-76 air tanker and other aircraft were brought in to douse the flames.
President Vladimir Putin spoke by telephone with the region's governor and ordered him to find a way to rebuild the homes that were destroyed, the Kremlin said in a statement.
Russia has been hit with huge forest fires in recent years, including in far-flung remote regions.