At least 32 people have been confirmed dead and hundreds of families displaced after the walls of Patel Dam in Solai, a town 190km north-west of the capital, Nairobi, broke down on Wednesday night.
Region police boss Japheth Kioko on Thursday said 32 bodies had been recovered, with search and rescue operation ongoing.
There are fears of the toll rising further because "many people" are still unaccounted for, according to local leaders.
Residents told the Nation that they heard an "explosion" before water gushed out, sweeping away hundreds of homes in the neighbourhood, including those on the expansive Nyakinyua Farm, which borders the water reservoir.
The 9pm horror rendered over 300 families homeless and about 2,500 residents were affected.
Property estimated to be worth millions of shillings was also destroyed by the raging waters and thick mud.
Tens of people, including children, are feared trapped in the black mud.
Rescue operation by Kenya Red Cross and Nakuru County disaster management teams went into the small hours of Thursday.
By 1am, about 40 people had been rescued from the mud and rushed to local health facilities, including Bahati Sub-County and Nakuru Level Five hospitals.
The rescue mission was called off at 2am due to darkness but resumed on Thursday morning.
The dam water and mud spilt out of the reservoir and submerged homes, extending to a radius of nearly two kilometres.
The mega dam is one of the three water reservoirs owned by a large-scale irrigation farmer, Mr Mansukul Patel, who was not around at the time of the tragedy.
The one that wreaked havoc is situated on the upper end of his expansive farm and initial reports indicate that it "burst" due to high volumes of water.
Its location on the upper side of the farm as locals live in low-lying areas has elicited many questions, with Nakuru Governor Lee Kinyanjui saying they will investigate if Mr Patel was licensed to set up the reservoirs.
The other two dams are intact but with with high volumes of water.
A team from both the national and regional governments is expected to assess them this morning.
Area representative Peter Mbae told the Nation that more than 20 families had been evacuated to safe grounds.
"We assure residents that the rescue teams are doing their best to evacuate affected families to safety and assist victims get medical attention,” said Mr Mbae.
Governor Kinyanjui said the flood waters caused huge destruction of both life and property.
The extent of the damage is yet to be ascertained, he said in a statement.
“The county has dispatched ambulances to the scene to aid in evacuation of victims,” he said.
“Medics have been mobilised at Bahati Sub-County Hospital and Nakuru County Referral Hospital and are on standby to receive victims.”
Mr Kinyanjui said they were doing their best to evacuate affected families to safety and assist victims get medical attention.
“We urge residents to continue to be vigilant due to flooding caused by heavy rains experienced in the county and other parts of the country,” he said.
He said the county government will donate foodstuffs and other items to the displaced families on Thursday.
A centre, he said, has been set up near the scene for families to report missing members.
"This will enable us reunite families who may have separated from their loved ones during the incident," he said.