Flash Flooding in New York, September 16 to 18, 1999

Name: Flash Flooding in New York, September 16 to 18, 1999
Start: 1999-09-16T11:08
End: 1999-09-18T03:00
Location: New York

September 16 to 18, 1999 · NWS OKX · 11 events in 11 counties and zones

Property Damage: Orange, Putnam, Rockland, and Westchester Counties were declared disaster areas. 6 million dollars.

Where it happened

Every event with a place to put it; 11 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 1
Injuries: 0
Property damage: $15 million
Crop damage: None recorded
Events: 11

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS OKX wrote it up.

Torrential record rainfall, which caused serious widespread urban, small stream, and river flooding, preceded the remnants of Hurricane Floyd, which passed over Western Suffolk County of Long Island from 7 pm to 9 pm on September 16th.Death: In Rockland County, a 53-year old man died around midnight on the 17th when he was swept into the Pearl River while walking in Orangetown.Property Damage: Orange, Putnam, Rockland, and Westchester Counties were declared disaster areas. For these 4 counties, the initial cost estimates were $14.6 million dollars. These figures represents "eligible" costs for disaster payments, and were provided by the New York State Emergency Management Office. They represent a "fraction" of the costs that were actually incurred.Urban Flooding: Serious widespread flooding of low-lying and poor drainage areas resulted in the closure of many roads and basement flooding across the entire region.Stream and River Flooding:In Rockland County, the Mahwah River at Suffern was above its' flood stage of 4 ft. from 1:30 pm on the 16th until 3 am on the 18th. The crest stage was about 9.7 feet.In Westchester and Bronx Counties, the Saw Mill and Bronx Rivers overflowed their banks and caused serious widespread urban flooding.Rainfall Amounts: The axis of heaviest rain was oriented from southwest to northeast and extended from Central NJ northeast across the Lower Hudson Valley of Southeast NY and Southwest CT. Maximum rainfall rates from 1 to around 2 inches per hour lasted for at least 3 consecutive hours across parts of the Lower Hudson Valley from 2 pm until 6 pm on the 16th.Here are selected rainfall amounts for:Putnam County: from 11.73 inches at the George Fischer M.S. Weather Station in Carmel to 13.70 inches at Brewster. Rockland County: from 7.85 inches at Pomona to 10.17 inches at Congers.Westchester County: from 5.03 inches at Tuckahoe to 12.55 inches at Granite Springs. At Westchester County Airport, 6.26 inches was measured.Orange County: from 4.46 inches at Middletown to 8.25 inches at West Point.Bronx County: 7.51 inches was measured by the Fordham Prep School Weather Station.New York (Manhattan) County: from 4.06 inches at the Saint Rose of Lima Weather Station to 5.02 inches at Central Park.Richmond (Staten Island:) County: No reports were available.Kings (Brooklyn) County: from 3.83 inches at Graves End to 5.53 inches at the Bishop Kearney H.S. Weather Station.Queens County: from 3.27 inches at JFK Airport to 4.94 inches at LaGuardia Airport.Nassau County: from 3.67 inches at Wantagh to 4.12 inches at Mineola.Suffolk County: from 2.67 inches at Bridgehampton to 4.88 inches at Sea Cliff.Winds: Strong and gusty winds combined with torrential rain downed many trees, tree limbs, and power lines across the area. Significant power outages resulted. Most wind gusts were from 50 to 60 mph from around 1:30 pm on the 16th to around 2 am on the 17th.

The radar

The Brookhaven radar (KOKX), 89 km away, was scanning. The volume nearest the first event began at 16:06 UTC.

Open the radar archive at this moment

Event by event

11 flash flood. Local standard time, as filed.

Flash Flood, Bronx

When: September 16, 11:08 AM EST to 7:00 PM EST
Where: Bronx County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 40.827, -73.924 (the zone’s center; the record gives no point)

Flash Flood, New York

When: September 16, 11:08 AM EST to 7:00 PM EST
Where: New York County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 40.774, -73.970 (the zone’s center; the record gives no point)

Flash Flood, Richmond

When: September 16, 11:08 AM EST to 7:00 PM EST
Where: Richmond County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 40.583, -74.150 (the zone’s center; the record gives no point)

Flash Flood, Kings

When: September 16, 11:08 AM EST to 7:00 PM EST
Where: Kings County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 40.634, -73.950 (the zone’s center; the record gives no point)

Flash Flood, Queens

When: September 16, 11:08 AM EST to 7:00 PM EST
Where: Queens County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 40.658, -73.839 (the zone’s center; the record gives no point)

Flash Flood, Nassau

When: September 16, 11:30 AM EST
Where: Nassau County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 40.732, -73.585 (the zone’s center; the record gives no point)

Flash Flood, Rockland

When: September 16, 12:00 PM EST to September 18, 3:00 AM EST
Where: Rockland County, Countywide
Deaths: 1 direct, 0 indirect
Property damage: $4.4 million
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 41.152, -74.024 (the zone’s center; the record gives no point)

Flash Flood, Westchester

When: September 16, 12:00 PM EST to September 17, 2:00 PM EST
Where: Westchester County, Countywide
Property damage: $6.6 million
Reported by: TRAINED SPOTTER
Coordinates: 41.152, -73.753 (the zone’s center; the record gives no point)

Flash Flood, Suffolk

When: September 16, 12:45 PM EST
Where: Suffolk County, Countywide
Reported by: EMERGENCY MANAGER
Coordinates: 40.941, -72.685 (the zone’s center; the record gives no point)

Flash Flood, Orange

When: September 16, 2:15 PM EST to September 17, 2:00 PM EST
Where: Orange County, Countywide
Property damage: $1.7 million
Reported by: TRAINED SPOTTER
Coordinates: 41.402, -74.306 (the zone’s center; the record gives no point)

Flash Flood, Putnam

When: September 16, 2:15 PM EST to September 17, 2:00 PM EST
Where: Putnam County, Countywide
Property damage: $1.9 million
Reported by: EMERGENCY MANAGER
Coordinates: 41.427, -73.749 (the zone’s center; the record gives no point)

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Flash Flood, Rockland	1999-09-17	53	Male	Outside/Open Areas	Direct

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in New York in 1999 Every state in 1999 This day in weather history Warnings in New York, September 1999

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 5724747, 5724748, 5724749, 5724750, 5724751, 5724752, 5724745, 5724746, 5724753, 5724743, 5724744.