Friday, June 24, 2016

Flooding in Appalachia

Yesterday afternoon and evening, a line of strong thunderstorms stretched across the Appalachians, from the Ohio River Valley to south-central Virginia.  Aligned along a stationary front and steered by the jet stream, the storms "trained" over the same areas, unleashing torrential rain (up to 9 inches in some locations).

Falling on the dissected terrain of the Appalachian Plateau and the Ridge and Valley topography west of the Blue Ridge, the copious precipitation drained rapidly from the steep ridges to the primary river valleys; mudslides and valley floods were the result, most severe in southeastern West Virginia and adjacent sections of Virginia.  Unfortunately, most Appalachian towns lie within the valleys and widespread damage has been reported.

Flash flooding is especially dangerous in mountainous terrain since it develops rapidly and escape routes are often limited.  Those living in or visiting such regions are thus advised to heed weather forecasts and take note of potential routes to higher ground; multiple routes should be considered since some roads may be closed due to high water or mudslides.  Beautiful as it may be in sunny weather, mountainous terrain poses unique risks when thunderstorms approach, even when heavy rains fall far upstream.