After a severe storm caused transportation disruptions and structural damage
throughout New York City on August 8, 2007, Mayor Bloomberg launched the Flood
Mitigation Task Force to coordinate and enhance the City’s response to flooding
and leverage the capabilities of each agency to address storm-water management.
One of the goals of the task force was to develop a comprehensive citywide plan
to improve residents’ flood
preparedness (PDF, 1.59 MB) and ability to recover from flash
floods. Get Adobe Acrobat
HAZARD DEFINITION: FLASH FLOOD
A flash flood is a rapid rise of water along a stream or in a low-lying urban
area. Most flash flooding is caused by slow-moving thunderstorms, thunderstorms
repeatedly moving over the same area, or heavy rain from hurricanes and tropical
storms. Densely populated urban areas are at particular risk for flash floods
because most surfaces are paved and impermeable. Very little rainfall in New
York City is absorbed by the ground. Instead, most of it flows into street-level
catch basins and then into sewers. Periods of intense rain can overwhelm
storm sewers and cause flash floods. Clogged or obstructed catch basins can
lead to flooded street corners, underpasses, underground parking garages, and
basements.
OVERVIEW OF THE PLAN
The Flash Flood Emergency Plan describes a coordinated response to flash
floods in New York City. The plan contains detailed procedures to minimize a
flood’s effects on New Yorkers and their property.
PLAN OBJECTIVES:
Reinforcing weather monitoring protocols among City agencies to increase
situational awareness
Targeting stormwater infrastructure for maintenance in recurring flood
locations
Monitoring flood-prone locations during intense rain to target
maintenance, emergency response, and recovery
Providing recovery assistance to affected populations following a flash
flood
