Note on Article in BHS Newsletter ‘Circulation’, 120, February 2014 5-7

David Archer and Hayley Fowler ‘Do floods cause more loss of life from the peak or from their rate of rise?’

The brief paper argues that the speed of onset of flooding is a key factor in causing loss of life because it can trap householders in places from which they cannot escape. The paper gives examples of historical flash floods with rapid rates of rise where multiple deaths occurred, including the well-known flood on the Lud at Louth in 1920 (23 deaths) but also at Barnsley in 1838 (27 deaths there and 5 elsewhere), near Truro in 1846 (39 deaths). The paper also describes a more recent flood where a ’10 foot wall of water’ swept a boy to his death on the River Gelt in June 1982 and a similar event on the West Allen in Northumberland where a swimmer narrowly escaped. Flood waves generated in the headwaters of the River Tyne can persist with very rapid rates of rise and sometimes with a steepening wave front 80 km downstream to the estuary. Such an event occurred in July 2002 and although it caused no loss of life, it is clear that such events pose great risks to river users notably fishermen who may stand knee-deep in water some distance from the water’s edge. With the flood discharge rising by 160 m3 sec-1 in 15 minutes, they would have less than a minute to escape. The article does not specifically answer the question in the title but it shows that there is a different category of risk from that associated with the peak flow. The intention of the FRANC and SINATRA projects to address such issues as meteorological forecasting, hydrological modelling and forecasting of such flash flood events is noted.

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