Abstract Alluvial fans and fluvial fans are the most common depositional landforms along the margins of continental sedimentary basins. Their occurrence is determined by the area, relief and hydrology of the catchment, which ultimately control the relative ratios of sediment v. flow discharge and runoff regimes. Fundamental morphological and process distinctions exist between these two kinds of deposystem, which are seen as essentially different facies associations and internal architectures for the corresponding deposits. Alluvial fans commonly develop over short radial distances (hundreds of metres to a few kilometres) and are constructed by ephemeral, flash flow events that lead to poor organization of the sedimentary facies and overall architecture of the corresponding deposits. By contrast, fluvial (mega)fans are fed by proper river systems, which aggrade much larger volumes of clastic sediment over distances of up to a few hundred kilometres. Distinct channel belt and overbank domains are developed with a marked heterogeneity in the distribution of sedimentary facies, represented by hierarchically well-organized fluvial deposits. The general properties of alluvial and fluvial fans reflect the different potentials for the corresponding successions to host economically attractive oil and gas resources and the different approaches required in exploration and prediction.

Abstract The 2.4-km-long Proffit Mountain flood scour formed when the upper reservoir of the Taum Sauk Power Plant, a reversible pumped electric storage facility, failed on 14 December 2005. Approximately 1.3 billion gallons of water drained from the reservoir in roughly 12 minutes, scouring a small tributary on the west flank of Proffit Mountain to bedrock and depositing debris in the valley floor and in the valley of the East Fork of the Black River. The stratigraphic succession exposed includes Mesoproterozoic Taum Sauk Rhyolite and Munger Granite, Cambrian conglomerate and dolomite and flood deposits. The site provides a unique opportunity to study a landscape-scale outcrop.

The Dead Sea, located along the boundary separating semiarid climate from arid climate, is prone to flash flooding caused mainly by severe convection generating heavy precipitation. An overview of the main responsible synoptic systems (tropical and extra-tropical) accounting for most of the major flash floods is presented. The moisture for developing intensive convection over the region can be originated not only from the adjacent Mediterranean Sea but also from distant upwind sources. Under tropical air mass intrusions, convection generated by static instability seems to play a more important role than synoptic-scale vertical motions. The essential subsynoptic scale processes leading to deep convection and the resulting spatio-temporal rainfall characteristics are discussed through examples of selected storms previously analyzed.