Thursday, 2 August 2001
A River and Flash Flood Climatology of Southern New England: Results from 1994–2000
The National Weather Service in Taunton, Massachusetts assumed its Hydrologic Service Area (HSA) in November, 1994, extending from the lower Connecticut River Valley eastward to coastal Massachusetts. This study reviews all flood and flash flood events during the period 1994-2000, separated into two distinct categories. These categories include flash flood, which is flooding that occurs in the 0 to 6 hour time frame but is not strictly limited to true flash flooding associated with short duration heavy rainfall; and flood, which is defined as all flooding that occurs in 6 to 24 hours and is generally associated with larger mainstem river flooding.
Although the results are somewhat skewed by major flood episodes in October, 1996 and June, 1998, the results clearly depict preferred regions susceptible to flash floods as well as preferred times of year for their occurrence. The results will also show that mainstem river flooding, while observed nearly every month of the year, is more frequent in the spring due to snowmelt and that nearly all of the significant river flood events studied were the result of either back-to-back heavy rainfall events or the influence of a tropical cyclone.