The Kenya National Disaster Operation Centre

Landslides are described as the downward movement of soil and rocks resulting from naturally occurring vibrations, changes in water content, removal of lateral support, loading with weight and weathering or human manipulation of water courses and the composition of the slope.

In Kenya landslides and mudslides occur mostly during the rainy season and are accelerated by flooding. Usually they affect parts of the country like western, Nyanza and north Rift Valley provinces, however the most vulnerable areas have been the following: - Murang’a district in central province, Kirinyaga, Nyeri, parts of Meru, which are areas around the mount Kenya region, Kisii and Mombasa Island. These are areas with annual rainfall of over 1200 mm and steep slopes.

Landslides are triggered by rapid saturation of the soil, which in turn reduces cohesion, surface tension and friction. The El Niño rains experienced between October 1997 to February 1998 have exacerbated the landslide hazards, thus calling for an urgent need to set up early warning systems in Kenya.

Mudslides have become more common in Kenya because forests have been cleared to make way for farmland. The soil becomes loose and flows down slopes, leading to destruction of property and death.