In this area, precipitation mainly occurs in the form of heavy showers followed by flash floods. Precipitation levels can reach up to 1.500 mm/yr on the southwestern mountain slopes in Yemen.38 Some moderate seasonal shifts in rainfall patterns and intensities have also been observed in the region in recent years. According to the IPCC Fourth Assessment Report,3’ the Arab region is highly vulnerable to the potential impacts of climate change, which include higher average temperatures, less and more erratic precipitation and sea-level rise.