The storm morphology of deadly flooding events in the United States

Abstract

This study investigates the synoptic and mesoscale environments associated with deadly flooding events in the United States from 1996 to 2005. A manual environment classification scheme, which includes analyses of surface charts, 500 hPa maps, and composite radar data (where available), is utilized to ascertain the primary ascent mechanisms and storm types producing these fatal flood events. Of the ten classifications in the scheme, the two most dominant ascent mechanisms associated with deadly floods include frontal boundaries (45%) and tropical systems (22%). Findings illustrate that mesoscale convective systems were responsible for 36% of the total number of flood fatalities over the period. The ten classifications are spatially and temporally analysed in order to assess region-specific risks associated with deadly flooding events.

An examination of rip current fatalities in the United States

“…Changnon and D. Changnon 1999;Curran et al 2000;Ashley and Mote 2005;Ashley and Ashley 2008a, b;and Gall et al 2009) because of the underreporting of both casualties and damage estimates. However, as also noted by Ashley and Ashley (2008b), fatal weather events are more likely to be reported due to enhanced media attention. Therefore, Storm Data provides researchers with an adequate first estimate of the actual number of fatalities for given oceanic and atmospheric events.…”

Climate extremes in the United States: recent research by physical geographers

“…These contingencies may explain why Changnon and Hewings (2001) found that annual measures of the areal extent of the United States experiencing heavy precipitation were poorly correlated with annual US flood losses from 1950 to 1997 -despite significant upward trends in both heavy precipitation events and flood losses over the same period. Most US flood fatalities have been associated with heavy rainfall events: Ashley and Ashley (2008a) reported that 88% of flood-related fatalities across the contiguous United States from 1996 to 2005 (exclusive of hurricane Katrina) were due to flash floods or tropical system floods; Ashley and Ashley (2008b) similarly found that flash floods and tropical system floods were the deadliest flood types in the contiguous United States from 1959 to 2005. Flood deaths due to flashy precipitation peaked in the summer to early fall (Ashley & Ashley, 2008a); flash flood fatality rates were highest in Southwestern and South Central states, the Ozarks, and the Appalachians from Tennessee to Pennsylvania (Ashley & Ashley, 2008b).…”

“…Extreme rainfall often affects society through flooding, and studies have found strong connections between heavy rainfall events and increased peak streamflow (Changnon & Demisse, 1996;Robinson, 2003) and between heavy rainfall and flood events (Ashley & Ashley, 2008a). However, physical geographers have stressed that this connection between heavy rainfall and floods is heavily contingent on the local geography of affected basins, including land-use and drainage (Changnon & Demisse, 1996), and seasonality, soil moisture, and precursor events (Robinson, 2003).…”

“…However, several works discussed physical processes underlying floods. For example, both Robinson (2003) and Ashley and Ashley (2008a) examined synoptic causes of floods, and Ashley and Ashley (2008a) also discussed mesoscale environments.…”

“…For example, Ashley and Ashley (2008a) focused on synoptic and mesoscale causes of fatal flood events, and Nicholls (2001) discussed the importance of forecasts across spatial and temporal scales to mitigate climate extreme impacts. Other studies were conducted at a range of spatial scales, from subnational (Changnon, 2005;Montz & Tobin, 2008;Robinson, 2003;Todhunter & Rundquist, 2008) to national (Changnon & Changnon, 1998;Changnon, 1999aChangnon, , 2003cChangnon & Hewings, 2001;Riebsame et al, 1986).…”