(Bloomberg) -- Parts of Russia and neighboring Kazakhstan are battling their worst floods in about 80 years after unexpectedly high temperatures melted an unusual amount of snow that had accumulated on and around the Ural Mountains.

Russia has evacuated more than 30,000 people in Kurgan and Orenburg since early April, according to local authorities. While flooding has begun to ease in those regions, it has been intensifying in the Siberian Tumen area, where more than 1,500 people have been moved and a dam is in danger of collapsing.

In Kazakhstan, authorities asked more than 118,000 people to leave their homes, though about 20,000 have already returned, according to an April 19 statement from the emergency ministry.

There are signs that climate change is supercharging the floods, which Russian authorities said are the heaviest since 1942. Data from the country’s hydro-meteorological center shows vast parts of Russia have been experiencing abnormal warmth since the second half of March. In Moscow, temperatures reached 17C at the end of the month, the highest in more than 40 years. Cities in Kazakhstan have also broken decades-long heat records.

The abrupt temperature increase this spring, combined with high snow reserves, increased humidity and soil freezing to cause the flooding, according to Natalia Frolova, a professor in the geography department at Moscow State University. “Global warming possibly contributes to an increase in the frequency of such anomalies, as well as in an increase in precipitation during the cold period, earlier snowmelt and other factors,” she said.

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In Russia’s regional capital of Orenburg, a city of about 500,000, many had to flee multistory residential buildings when the water arrived. Citizens demanded inflatable boats and water-resistant clothes while the government urged people to drink only bottled and boiled water and started a campaign to prevent Hepatitis A.

Larisa, a 58-year-old Orenburg resident who only provided her first name, said the warnings broadcast on local television “every few minutes” and also advised people to clean fruits, vegetables and dishes with boiled water. “Now I wash myself in the shower with apprehension,” she said. “It is not known what is going on with this water.”

In Kurgan, the government urged residents to ensure they have enough water to last for at least a month, according to a 54-year-old literature teacher who goes by Elena. Many residents put their hopes in a new dam that was erected about eight years ago to stem the flood, she said. But authorities said the dam has begun to leak in several places and that they’re working to reinforce it.Elena still remembers the last big flood that hit the city in 1994. “This flooding is much more serious,” she said.

“The existing evidence to date suggests that heavy precipitation events and warmer temperatures have increased in eastern central Asia and western Siberia since pre-industrial times,” said Ben Clarke, a researcher at the Grantham Institute at Imperial College London. “There is a high level of confidence that temperatures are much higher due to human-caused climate change, which leads to more rapid snowmelt.”

Russia declared a state of emergency in affected areas while President Vladimir Putin urged government officials to promptly restore infrastructure. The region is the home to several industrial facilities, including the Orsk oil refinery, which had to temporarily suspend work following intensified flooding after a dam collapse. Another dam in Kurgan is also leaking.

Kazakhstan President Kassym-Jomart Tokayev also declared a state of emergency in 10 out of the country’s 17 regions on April 6 and ordered a “regime of tough thriftiness” so money from the state budget can be rerouted to help flood victims. Work at more than 600 oil wells was suspended, resulting in 16,000 tons in lost oil production, according to the energy ministry.

The economic impact from flooding in both countries is still unclear. Kazakhstan’s central bank halted its longest series of interest-rate cuts in nearly a decade on April 12, citing the disaster as one of the reasons. There’s a “certain uncertainty in terms of the consequences,” Governor Timur Suleimenov said.

Denis Pasler, the governor of Orenburg in Russia, gave a preliminary estimate of about 40 billion rubles (over $400 million) in damages.

The “floods were truly unprecedented in scale and were difficult to predict,” said Vladimir Slivyak, a climate expert and co-founder of Ecodefense, an environmental group based in Germany. “Such natural disasters will get stronger and bigger and will occur often.”

--With assistance from Laura Millan, Ilya Arkhipov and Irina Reznik.

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