On Friday night and Saturday morning, a torrential downpour ripped through the Black Sea region of southern Russia, causing massive floods. By Sunday, the death toll reached 150 and is expected to rise as more bodies are discovered. More than 5,000 homes have been flooded.

The disaster, which affected thousands of residents in the Krasnodar Krai region, was most devastating to the city of Krymsk, about 20 miles inland. The vast majority of the deaths confirmed so far occurred in this city of 57,000 people.

Other fatalities occurred in Novorossiysk, a port city, and Gelendzhik, a resort town -- both of which border the Black Sea.

Russian news outlet RT reports that the nature of the flooding in these three cities was very different. In Novorossiysk and Gelendzhick, the flooding progressed as would be expected from a sudden rainstorm -- it washed down from the surrounding mountains and into the sea, gushing through residential areas on its way and killing several people.

But in Krymsk, the deluge was brutally sudden. Witnesses compared the event to a tsunami, saying their town went underwater in a matter of minutes.

Most were asleep when the disaster occurred, making it difficult for Krymsk residents and safety officials to respond quickly enough to avoid mass fatalities.

Immediately, suspicions erupted over the exact cause of the flooding. Anti-government activists pointed to the nearby Neberdzhaevskoye reservoir, blaming the flood on a technical mistake. They surmised that authorities had opened up the sluices in order to avoid damage to the reservoir infrastructure, an ill-timed mistake that became fatal amid unexpected downpours.

Local authorities first said that the sluices were impossible to open, denying the claims outright. But the Investigative Committee, a federally appointed body charged with determining how the fatalities occurred and whether a better emergency response could have been implemented, came back with a different answer. They affirmed that water had been released from the reservoir, explaining that it was carried out according to a routine schedule and was not the main cause of the deluge.

The investigation has found that the discharge of water was carried out in a normal fashion, the reservoir was not overflown. ... No mass discharge has been registered, said Investigative Committee spokesman Vladimir Markin to RT.

Authorities also added that even if the dam did overflow, the discharge would drain away from, not toward, the town of Krymsk.

Instead, officials point to the fact that the town in in the middle of a large valley. It is also traversed by the Adagum River, which collects several tributaries from the mountains before it runs through Krymsk. They attributed the calamity to a tragic confluence of topographical and climatological factors.

Russian President Vladimir Putin is making efforts to attend promptly to the disaster -- he has been accused of sluggish responses to past emergencies. On Saturday, he flew over the flooded region in a helicopter to survey the damage.  He asked the Investigative Agency to look into possible preventative measures that could have been taken.

Putin also instructed Emergencies Minister Vladmir Puchkov to inspect the Neberdzhaevskoye reservoir and dam, according to the Los Angeles Times. On Sunday, Puchkov said that the infrastructure was intact.

Meanwhile, rescue workers continue in their efforts to locate missing survivors, and to find and identify the bodies of drowned victims. Putin has decreed reparations of about $60,800 for the families of those who died. Repairing demolished municipal infrastructure will be the next step. The local bus service in Kyrmsk is already running again, as are railway systems.

Sunday has been declared a day of mourning for all those who have lost their lives.