Flash flood hazard in the mountainous area of Southwestern Sinai demands reliable and accurate information. Flash flood is the mainly dangerous hazard to spotlight on because it threats the life of people and retards any sustainable development planning in and around the rugged topography areas. The current study aims to applying GIS and remote sensing tools to construct flash flood hazards map based on geomorphometric parameters extracted from Digital Elevation Model (DEM) and assess the flash flood hazard risk rank for W. Baba basin and its sub-basins. Wadi Baba is located in an arid region and is considered as a significant basin in Southwestern Sinai area (SWSA) that drains into the Gulf of Suez. The drainage networks and basin boundary were delineated and morphometric parameters of the drainage system were calculated. The flood intensity is controlled mainly by values of geomorphometric parameters, soil and geological characteristics, and the meteorological conditions. The analysis of the various morphometric parameters of the W. Baba shows that they have different impacts on the flash flood intensity. Depending on the statistically computed weights and mean values of the important geomorphometric parameters and then integrated by using GIS functions; the sub-basins of W. Baba are classified into three categorized risk wise, namely: high, moderate and low flash flood hazard. The sub-basins which have high flash flood hazard rank with low probability of ground water recharge are geospatially mapped.