North Country Flash Flood - Severe T'Storm Event
Hoosick Falls Severe Flash Flood
100 mph Microburst @ Sandgate, VT - Bennington County
Saturday, July 1, 2017

A significant rain/thunderstorm event unfolded across mainly the northern portion of the region through the day on Saturday July 1, 2017 affecting primarily Herkimer, Hamilton, Fulton, Warren, northern Saratoga, Washington, and Rutland counties. Multiple rounds of downpours and t'storms, a few of which were briefly and locally severe, tracked from west to east over the same areas from the early morning through the late afternoon and early evening producing 2"-5" of rainfall on average, coming after pockets of heavy rain fell in the region the day before. The result was significant flash flooding in southern Herkimer County (where the soil is largely clay based making Herkimer county particularly prone to flash flooding) as well as across portions of Warren County near Glens Falls and in Washington County, especially along the Mettawee River in Granville where some 5.00" plus rainfall amounts were recorded by our WeatherNet 6 spotters.

Across the remainder of the region, generally dry, hot, and oppressively humid weather (dewpoints ranged from the upper 60s to lower 70s) prevailed with little in the way of rainfall. It was not until the late afternoon and early evening that a line segment of strong thunderstorms moved down the Mohawk valley into the Capital Region to Bennington,VT. A small rotating cell in the northern portion of the line unleashed a 100 mph microburst on the town on Sandgate, VT in Bennington County, just west of Manchester, at approximately 6:38pm with was responsible for significant tree damage in the town. The radar image below is the velocity scan close to the time of the microburst showing a clear rotational couplet over the region.

Albany Doppler Radar lowest tilt storm relative velocity - rotational couplet indicated in the area outlined by the yellow arrows at about the time of the 100 mph microburst in Sandgate.
Storm Relative Velocity at the approximate time of the 100 mph microburst in Sandgate, VT, Saturday July 1, 2017

The southern portion of the line stalled out over southern Bennington and northern Rensselaer counties through 9-10pm unleashing a torrent of rainfall ranging from 3"-5" from Pownal, VT to Hoosick Falls which lead to a severe flash flood event throughout the village of Hoosick Falls. The ample moisture in the atmosphere was the prime contributor to the heavy rainfall with flash flooding enhanced due to the local topography. Our WeatherNet 6 spotter in nearby Speigletown just west of Hoosick Falls measured 1.80" of rainfall between 6:00pm and 7:30pm with a total of 2.8" through 10pm. This, as generally dry weather prevailed across the remainder of the region.

Photograph by Pamela Benkosk: Severe flooding in progress in Hoosick Falls, Rensselaer County, Saturday evening July 1, 2017

Flooding in progress in Hoosick Falls, Saturday July 1, 2017 

Photograph by Pamela Benkosk: Severe flooding in progress in Hoosick Falls, Rensselaer County, Saturday evening July 1, 2017

Albany NWS storm relative velocity, 3:49pm June 30, 2017 

The following three photographs by Steve Bradley via facebook: Flooding in progress in Hoosick Falls, Rensselaer County, Saturday evening July 1, 2017


Flooding in progress in Hoosick Falls, Saturday July 1, 2017

Flooding in progress in Hoosick Falls, Saturday July 1, 2017 

Flooding in progress in Hoosick Falls, Saturday July 1, 2017 

Overall, the number of severe weather reports across the region was quite small with the main impacts from the event being flash flooding across the northern tier counties as well as the isolated and very localized flash flooding in Hoosick Falls and across southern VT. A wider and more substantial severe event would have occurred had lapse rates (the cooling rate with height) been better as ample wind shear (turning and increasing of the wind with height) as well as a high degree of moisture and heat were available to support a significant severe event along the leading edge of an approaching mid level short wave trough.

WeatherNet 6 Rainfall Reports for Saturday July 1, 2017

Town
County
Rainfall Report
Town
County
Rainfall Report
Savoy, MA Berkshire 0.20"      
           
Westmere Albany 0.43" Glenmont Albany 0.58"
           
Taghkanic Columbia 0.08"      
           
Arkville Delaware 0.20" Roxbury Delaware 0.13"
           
Greenville Greene 0.11" Catskill Greene 0.08"
           
Northville Fulton 2.97" Fish House Fulton 2.00"
Broadalbin Fulton 1.00"      
           
Wells Hamilton 2.92" Piseco Hamilton 2.50"
           
Amsterdam Montgomery 0.27" Fonda Montgomery 0.38"
Palatine Bridge Montgomery 0.27"      
           
Oneonta Otsego 0.10"      
           
Speigletown Rensselaer 2.80" (Between 6pm and 10:30pm, 1.80" of it between 6 and 7:30pm) Center Brunswick Rensselaer 1.42"
3 Miles WNW Hoosick Falls Rensselaer 4.35" (NWS)      
           
Milton Saratoga 0.69" Lake Desolation Saratoga 1.01"
Clifton Park (Oaks) Saratoga 1.10" Saratoga Springs Saratoga 1.69"
Town of Day Saratoga 3.07" Malta Saratoga 0.99"
           
Rotterdam Schenectady 0.54"      
           
Queensbury Warren 2.05" Lake Luzerne Warren 3.53"
Glens Falls Warren 3.30" (NWS)      
           
Whiteport Ulster 0.20"      
           
Hudson Falls Washington 5.10" Fort Edward Washington 4.52"
Hartford Washington 5.00" Hebron Washington 3.56"
           
Woodford, VT Bennington 1.02" Landgrove, VT Bennington 0.92"
West Rutland, VT Rutland 1.18" Pownal, VT Bennington 3.10"

NWS Storm Severe and Flash Flood Reports for Saturday July 1, 2017. Note, these reports are used to verify the NWS warnings which were issued for this event and therefore do not necessarily represent an accounting for all of the wind damage or flooding which may have occurred.

Town County Severe Weather Report Time
Moreau Saratoga Lightning: Strikes on two buildings 9:06am
Glens Falls Warren Wind: Large maple limb, 4.5" in diameter and 12' long down 9:06am
Newport Herkimer Flash Flood: Mudslide near newport along route 28 1:00pm
3 Miles SSE Lynnwood Saratoga Wind: Trees blown down, power pole snapped 2:37pm
Queensbury Warren Wind: Tree blown down 3:10pm
2 miles NNE Countryman Herkimer Flash Flood: Route 28 closed due to flooding 4:00pm
1 Mile S. of Hague Warren Flood: Route 9, south bound lane closed due to flooding 4:05pm
1 Mile N. of Countryman Herkimer Wind: Trees blown down 4:10pm
1 Mile WSW East schuyler Herkimer Flash Flood: Person reported to have been trapped in a house due to flooding 4:10pm
Herkimer Herkimer Flash Flood: Route 5 closed from Schuyler to Little Falls due to flooding. Walmart evacuated due to flooding concerns 4:10pm (est.)
Frankfort Herkimer Flash Flood: West Main Street, Route 171, and Route 5S closed in Frankfort due to flooding. State of Emergency in effect for Frankfort 4:10pm (est.)
2 Mile NE of Stratford Fulton Flash Flood: Seely Road washed out 4:40pm
1 Mile SSE of Baldwin Corner Washington Flash Flood: Route 149 closed near the Route 4 intersection 4:50pm
1 Mile E. of Glens Falls Warren Flash Flood: Route 32 closed near the Haskell Ave. intersection 5:00pm
2 Miles WNW of South Granville Washington Flash Flood: route 149 eastbound and westbound closed at Searls Road due to flooding 5:15pm
1 Mile NE of Adamsville Washington Flash Flood: Roads closed and washed out 6:10pm
Sandgate, VT Bennington Wind: 100 mph microburst, path width of 500 yards, path length of 1 mile, significant damage to trees, no building involved, no injuries 6:38pm
Hoosick Falls Rensselaer Flash Flood: Severe flooding in multiple parts of the village. Flooding covered multiple roads, severely damaging roads and driveways, many roads into the village blocked due to flooding, multiple houses reported flooding in their basements with some up into the first floor, state of emergency declared 6:30pm-Midnight
1 Mile NNW of Haynersville Rensselaer Flash Flood: Cooksboro Road inundated 8:00pm
Hoosick Falls Rensselaer Flash Flood: Additional roads inundated including Church Street and Hall Street 8:25pm
2 Miles ESE of Raymertown Rensselaer Flash Flood: Water running over roads with road closures 9:50pm
1 Mile NE of Center Brunswick Rensselaer Flash Flood: Route 7 closed due to flooding between the Vermont state line in Hoosick and Brick Church Rd in Brunswick 9:50pm

 

Storm Reports for July 1, 2017 

Photograph by Steve LaPointe: Thunderstorm coming into Niskayuna, Schenectady County, just prior to 6pm, Saturday July 1, 2017. This is the CBS6 station parking lot with Instant Doppler 6 in the foreground. This was part of the line of storms which produced the 100 mph microburst in Sandgate, VT at 6:38pm. The nearly stationary thunderstorm over northern Rensselaer and southern Bennington counties responsible for the extreme flash flood event in Hoosick Falls also originated out of this thunderstorm line.

Instant Doppler 6 image at roughly 2:45pm Friday June 30, 2017 - Clusters of strong thunderstorms aligned to the west of the Hudson valley