Flash Flooding in New York, March 22, 1999

Two low pressure centers, one heading south from Canada and another one moving north from the southeast U.S., consolidated into one big storm over northeast Pennsylvania by late March 21. This area of low pressure then rapidly deepened as it tracked up the Hudson Valley. The system tapped both Gulf of Mexico as well as Atlantic moisture to dump 2 to locally in excess of 4 inches of precipitation across Ulster and Greene counties in less than a 12 hour interval. The majority of precipitation was in the form of liquid rain and resulted in rapid swelling of small creeks and streams across the area. Some of the tributaries came out of their banks flooding adjacent roadways and basements. The Rondout Creek at Rosendale in Ulster County crested at 18.8 feet...about 9 inches over flood stage. The Esopus Creek also spilled a few inches over its 11 foot flood state at Mount Tremper. In Greene County the Catskill Creek overflowed and forced some people to be evacuated from their homes. Colder air moved in later during the morning changing the precipitation to snow. The changeover and lower temperatures helped to slow down the runoff.