The combination of a slow moving cold front approaching from the west, and an abundantly moist and warm air mass in place, led to the development of numerous showers and thunderstorms across eastern New York and western New England during Wednesday afternoon and evening on July 29th.
Some of the thunderstorms were severe, producing isolated damaging winds.  In addition, several clusters of thunderstorms moved slowly, and trained across the same areas for several hours, producing torrential rainfall and resulting in significant flash flooding.
Trained spotters measured rainfall amounts of 4 to 7 inches within the most persistent thunderstorms over a 3 to 6 hour period, particularly near Kinderhook, and adjacent areas of northern Columbia and southern Rensselaer Counties. In addition to widespread flash flooding, the Kinderhook Creek also overflowed its banks, resulting in additional flash flooding.
As a result of the flooding, Amtrak train service was suspended early Thursday morning on July 30th between the Rensselaer Rail Station and Penn Station, in order for track and signal systems to be examined for flood damage in Hudson. The rail service resumed by early Thursday afternoon.

Flash Flood in GREENE, NEW YORK
From 29-JUL-09 15:00:00 to 29-JUL-09 19:45:00 (EST-5)
Location: WEST COXSACKIE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Training thunderstorms produced very heavy rainfall across eastern portions of Greene County Wednesday afternoon and evening, resulting in flash flooding. State Route 385, or Mansion Street, in Coxsackie was closed due to flash flooding from this heavy rainfall. Several other streets within the village of Coxsackie were also impassable Wednesday evening due to flooding.

Flash Flood in SARATOGA, NEW YORK
From 29-JUL-09 15:00:00 to 29-JUL-09 17:45:00 (EST-5)
Location: EDINBURG
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Flash flooding from heavy rainfall resulted in the closure of South Shore Road in Edinburg.

Flood in RENSSELAER, NEW YORK
From 29-JUL-09 21:00:00 to 31-JUL-09 05:00:00 (EST-5)
Location: STEPHENTOWN CENTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Flooding from antecedent heavy rainfall continued from Wednesday night into early Friday morning. Numerous roadways remained closed, and many basement pumpouts occurred during this time.

Flood in COLUMBIA, NEW YORK
From 29-JUL-09 19:20:00 to 31-JUL-09 05:00:00 (EST-5)
Location: STUYVESANT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Flooding from previous heavy rainfall continued from Wednesday night into Friday morning. Numerous roadways remained closed, and many basements were pumped out during this time.
As a result of the flooding, Amtrak train service was suspended early Thursday morning on July 30th between the Rensselaer Rail Station and Penn Station, in order for track and signal systems to be examined for flood damage in Hudson. The rail service resumed by early Thursday afternoon.

Flash Flood in COLUMBIA, NEW YORK
From 29-JUL-09 15:45:00 to 29-JUL-09 19:20:00 (EST-5)
Location: STUYVESANT
Flood cause: Heavy Rain
Property damage: 4.50M
Crop damage: 0.00K
Reported by: Law Enforcement

Training thunderstorms produced excessive rainfall, and major flash flooding across northern and central portions of Columbia County during Wednesday afternoon and night. The heavy rainfall also led to Kinderhook Creek overflowing its banks.
Numerous roadways were closed due to flooding, which included, but were not limited to, Route 28, Route 13 near Albany Turnpike, Route 295 near Schillings Crossing Road, Hennett Road, McCagg Road, Gun Road, and Novak Road in Chatham, Route 9H near Fischer Road, East Shore Drive, and State Route 203 near Chapel Drive in Kinderhook, State Route 20 near the Speedway in New Lebanon, and Route 9J in Stuyvesant. Novak Road in Kinderhook and Reed Road in Ghent were reportedly washed out.
Numerous campers were stranded in water and mud within the parking area and adjacent camping area at Lebanon Valley Speedway in New Lebanon.
In addition, in Red Rock, County Route 5 at County Route 24 was closed due to a mudslide, and in Hollowville, County Route 16 was also closed due to a mudslide.
The severe flooding also led to the declaration of a state of emergency for the towns of Stuyvesant, Kinderhook, and New Lebanon.
Preliminary damage estimates in Columbia County from the flash flooding were in excess of $4 million.

Flash Flood in RENSSELAER, NEW YORK
From 29-JUL-09 15:00:00 to 29-JUL-09 21:00:00 (EST-5)
Location: SCHODACK CENTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Significant flash flooding occurred in central and southern Rensselaer County Wednesday afternoon and evening, as a result of training thunderstorms which produced excessive rainfall, and caused Kinderhook Creek to overflow its banks.
Numerous roadways and bridges were closed, some of which were washed out.  The hardest hit areas included, but were not limited to, Nassau, Stephentown, Schodack, and Sand Lake.
In Nassau, a state of emergency was declared, and State Route 43 between Pikes Pond Road and Reno Road was closed due to flooding.
In Stephentown, the bridge at State Route 22 and Provost Road was deemed unsafe, resulting in the closure of a portion of Route 22. In addition, flooding closed a portion of South Stephentown Road between Garfield Road and Andrews Lane.
In Sand Lake, Bauer Road was closed due to a bridge washout.
In Schodack, Clove Road off State Route 43 was closed to due flooding.

Flash Flood in COLUMBIA, NEW YORK
From 29-JUL-09 13:20:00 to 29-JUL-09 19:20:00 (EST-5)
Location: STUYVESANT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Training thunderstorms produced very heavy rainfall across northern Columbia County. A large section of Route 9J near Stuyvesant was closed due to flash flooding from this intense rainfall.

Thunderstorm Wind in GREENE, NEW YORK
From 29-JUL-09 12:45:00 to 29-JUL-09 12:45:00 (EST-5)
Location: CLIMAX
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trees and limbs were reported down on Bronck Mill Road, located near Climax.

Lightning in ULSTER, NEW YORK
From 29-JUL-09 14:30:00 to 29-JUL-09 14:30:00 (EST-5)
Location: WOODSTOCK
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Trees and wires were reported down approximately 1 mile north of Woodstock due to lightning.

Thunderstorm Wind in ULSTER, NEW YORK
From 29-JUL-09 14:30:00 to 29-JUL-09 14:30:00 (EST-5)
Location: WITTENBERG
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A tree was reported down on Wittenberg Road, located approximately 1 mile west of Woodstock, due to strong thunderstorm winds.

Thunderstorm Wind in COLUMBIA, NEW YORK
From 29-JUL-09 14:30:00 to 29-JUL-09 14:30:00 (EST-5)
Location: KINDERHOOK
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Wires and a pole were reported down near Kinderhook due to strong thunderstorm winds.