Studying the extremes: hydrometeorological investigation of a flood-causing rainstorm over Israel

Abstract

Abstract. Analysis of extreme hydrometeorological events is important for characterizing and better understanding the meteorological conditions that can generate severe rainstorms and the consequent catastrophic flooding. According to several studies (e.g., Alpert et al., 2004; Wittenberg et al., 2007), the occurrence of such extreme events is increasing over the eastern Mediterranean although total rain amounts are generally decreasing. The current study presents an analysis of an extreme event utilizing different methodologies: (a) synoptic maps and high resolution satellite imagery for atmospheric condition analysis; (b) rainfall analysis by rain gauges data; (c) meteorological radar rainfall calibration and analysis; (d) field measurements for estimating maximum peak discharges; and, (e) high resolution aerial photographs together with field surveying for quantifying the geomorphic impacts. The unusual storm occurred over Israel between 30 March and 2 April, 2006. Heavy rainfall produced more than 100 mm in some locations in only few hours and more than 200 mm in the major core area. Extreme rain intensities with recurrence intervals of more than 100 years were found for durations of 1 h and more as well as for the daily rain depth values. In the most severely affected area, Wadi Ara, extreme flash floods caused damages and casualties. Specific peak discharges were as high as 10–30 m³/s/km² for catchments of the size of 1–10 km², values larger than any recorded floods in similar climatic regions in Israel.

Using Lightning Data to Better Understand and Predict Flash Floods in the Mediterranean

“…(Morin et al 2007). In Israel, the floods were heaviest in the Wadi Ara region in central Israel, as well as in the Dead Sea region (Fig.…”

“…5c) are also shown. The measured surface rainfall showed peak values of more than 115 mm in a 24-h period in the Wadi Ara region, while the radar estimates also show values greater than 200 mm of rainfall within several hours in the region of heavy flooding (Morin et al 2007). The location of the peak lightning activity is in good agreement with the peak rainfall amounts.…”

“…The parameters of the routing model are derived from topography data (Digital Elevation Model-DEM) and published tables. Peak discharge estimates were available for several locations (catchment sizes of 0.5-21 km 2 ) in the flooded region based on post-event analysis (Morin et al 2007). In Fig.…”

High-impact floods and flash floods in Mediterranean countries: the FLASH preliminary database

“…The government and municipalities had to provide 44 million NIS (8.8 million) in assistance for recovering the Wadi Ara villages. Maximum rainfall of 260 mm was recorded in the Wadi Ara Region, with precipitation accumulations varying between 100-150 mm over an area of 17 km 2 that produced a peak discharge of 122 m 3 /s in the Keini sub-basin, that has a total area of 10.5 km 2 (Morin et al, 2007). This event affected the provinces of Attica, Laconia and Lesvos (Fig.…”

Progressive development of water resources in the Middle East for sustainable water supply in a period of climate change

“…The use of these models is elucidated in 'Future predictions of moisture budget over the eastern Mediterranean based on super-high-resolution global model' (Alpert & Jin 2009). Yet, while the total amount of precipitation over the eastern Mediterranean is decreasing, the occurrence of extreme events is on the rise (Morin et al 2007).…”