Wednesday, April 30, 2014

Pensacola Flooding

The storm system that brought deadly tornadoes to Arkansas and Mississippi swept torrential rains across the Florida Panhandle over the past 24 hours; Pensacola received more than 20 inches of rain, flooding large parts of the city.

This destructive deluge resulted from a stalled cold front, curving southward from an upper level low over the Upper Midwest.  Just ahead (east) of the front, heavy thunderstorms ignited, moving northeastward along the front, carrying their copious load of Gulf moisture.  Tracking over Pensacola, this storm train dropped half of that city's annual rainfall in 24 hours; this precipitation amounted to almost 2/3 of the annual total for most Midwestern cities and a full year's total for Denver, Colorado (i.e. rain and snow combined).

While the sandy soil of Florida usually wicks away heavy rain before it causes flooding, copious precipitation over short periods of time (as occurred with this storm system) leads to flash flooding, destroying roads, bridges and adjacent structures.  Fortunately, the system has slowly moved eastward and the heavy rains ahead of the cold front have shifted to the north and east; unfortunately, this may lead to floods across the Southeastern States and the Mid-Atlantic region.