The major ethnic groups are the Dagodie, Sheekhaal, Ogaden Pokomo, many of whom are farmers, and the Orma, Wardey and Gadsan who are peaceful people . The county is generally dry and prone to drought. Rainfall is erratic, with rainy seasons in March–May and October–December. Conflicts have occurred between farmers and other people over access to water. Flooding is also a regular problem, caused by heavy rainfall in upstream areas of the Tana River. On 22 August 2012, in the worst violent incident in Kenya since 2001, at least 52 people were killed in ethnic violence in Tana River County between the Orma'wardey and Pokomo groups.