AP Photo/Ignat Kozlov

MOSCOW - The death toll from this weekend's catastrophic flash floods in southern Russia has climbed to at least 171 people, and authorities warn that figure is likely to increase.

As the flood waters receded they revealed a grim sight. Dozens of bodies were reportedly found along the streets and inside homes. At least 15 remain unidentified. Local authorities said some may be unrecognizable, according to Russian news reports

Residents described a terrifying wall of water that caught many by surprise when it rushed into towns in the region of Crimea during the overnight hours on Saturday morning. The floods were said to be the country's worst in recent memory.

Those lucky enough to escape their homes reportedly climbed to safety on rooftops and in trees as flood waters quickly engulfed houses in low-lying areas.

Authorities estimate some 12,000 people were affected by the floods, which came after about 11 inches of rain - over an entire month's worth - fell that night.

Russian President Vladimir Putin flew to the affected areas on Saturday evening to survey the damage by helicopter. He pledged 10,000 rubles (about $300) in immediate emergency aid to victims' families and another $3,000 to compensate for loss of property, as well as government aid in rebuilding homes.

Putin also launched an investigation into why the death toll was so high. Residents said the waters arrived without warning and many pointed a finger at a nearby dam, which reportedly did not halt a scheduled release of water even as the floodwaters rose.