Roads and bridges have been either destroyed or severely damaged, cutting off villagers and leaving them without food or potable water, putting them at risk of cholera and other waterborne diseases.
The KRCS has begun trucking non-food items to Turkana and Nakuru in the northwest, where about 30,000 people have been affected in the past few days. The consignment includes blankets, jerry cans, mosquito nets, kitchen sets, soap and water treatment tablets.
These types of emergency activities are very expensive, said Abbas Gullet, KRCS Secretary-General. So far, the search and rescue activities have cost KRCS about KSh30 million (US$400,000), an amount sufficient to respond to the current needs but not if prolonged rains cause future damage, he added.
The organization has appealed for more funds to respond to the needs of the affected population in areas at high risk of cholera and other waterborne diseases.
"This has the potential of becoming an environmental disaster. We managed to address the immediate needs, but we need support to help our brothers and sisters," Gullet told IRIN.
"In some areas roads were completely washed away, impacting on search and rescue activities as well as the assessments to provide final figures of affected people and the number of deaths - which for now is recorded at 21 people," Colonel Joseph Kinwori of the National Disaster Operation Centre (NDOC) told IRIN.
According to NDOC, the area most badly affected by the floods is the North Rift Valley region. In one district, Turkana East, five people died, five bridges were destroyed, many farms and households were damaged, while hundreds of head of livestock perished.
Megan Gilgan, the UN Children's Fund (UNICEF) chief of emergency, told IRIN: "We are concerned about recurrences of watery diarrhoea and cholera in Lokori, East Turkana. The area already faced an unprecedented outbreak in the month of December and the situation could worsen now. We have emergency health kits available and water purification tablets for 30,000 people, enough supplies for a month."
Food supplies cut off
Local residents said the roads to Baragoi in Samburu and Kargi in Marsabit, in Eastern Province, were inaccessible.
Mohamed Kochale, a local leader in Marsabit, urged the government and aid agencies to help residents as they could not access markets to either buy food or seek healthcare.
He said hundreds of children in Marsabit were still at home and had not reported to school as roads were closed.
"Lorries, which are the only means of transport and are also used to ferry food, have been unable to reach some of the areas because the roads and bridges have been destroyed," he said.
Laikipia district Red Cross chairman Francis Wambua said more than 200 families had been displaced, their homes and farm produce destroyed, in Laikipia Mutaro area following the heavy rains on 3 January.
"The displaced families in Mutaro area need food assistance and shelter; their children have not gone back to school, they lost all their books and uniforms," Wambua told IRIN.
According to the Kenyan Meteorological Department, rains could continue into the first week of February. While this may cause further damage and displacement, it could also help reverse the severe food insecurity experienced across much of Kenya because of extreme drought in 2009.
"We can expect a good harvest for maize since at this time of the year crops are in filling stage, when they require lots of water," said John Kariuke, principal agriculture officer at the Ministry of Agriculture.