On 11 April 2010 at 7:40 icefall and rockfall from the Hualcán Mt. caused flood on the Chucchún River, right tributary of the Santa River, near the city of Carhuaz, department of Ancash. Direct damage comprises of aesthetical or functional damage to several residential houses located close to the river bad, loss of livestock and damage to the drinking water treatment plan. Geomorphologic mapping along the watercourse identified areas with prevailing type of fluvial processes. Detailed cross sections of the stream and adjacent valley slopes were constructed using laser range finder. Special attention was paid to identify flood sediments at each cross section. These data along with topography were used to model the flood in 1D HEC-RAS model. © Springer-Verlag Berlin Heidelberg 2013.