Flash Flood Warnings in New York, 2009

By month

53 of 98 flash flood warnings covering New York in 2009 had a flash flood report inside them; 93 of 119 flash flood reports fell inside a warning, on average 63 minutes after it went out.

New York, 2009

Each office's whole area, 2009

An office's figures cover every county it serves, including across state lines.

Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.

• Orange County9
• Westchester County7
• Chautauqua County7
• Rensselaer County6
• Wayne County6
• Cattaraugus County6
• Columbia County6
• Monroe County5
• Washington County5
• Delaware County5
• Ontario County5
• Allegany County5
• Putnam County5
• Rockland County5
• Saratoga County5
• Sullivan County5
• Dutchess County4
• Broome County4
• Chenango County4
• Schenectady County4
• Albany County3
• Otsego County3
• Suffolk County3
• Erie County3
• New York County3
• Kings County3
• Queens County3
• Cayuga County3
• Cortland County3
• Warren County2
• Hamilton County2
• Herkimer County2
• Montgomery County2
• Greene County2
• Bronx County2
• Genesee County2
• Niagara County2
• Orleans County2
• Livingston County2
• Steuben County2

1. August 10, 200918flash flood warnings
2. August 12, 200911flash flood warnings
3. July 1, 20098flash flood warnings
4. June 26, 20097flash flood warnings
5. July 29, 20096flash flood warnings
6. July 31, 20095flash flood warnings
7. June 30, 20094flash flood warnings
8. July 21, 20093flash flood warnings
9. July 26, 20093flash flood warnings
10. July 30, 20093flash flood warnings
11. August 23, 20093flash flood warnings
12. June 15, 20092flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20082010

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.