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Tropical Storm Irene
Severe to Catastrophic Flooding – High Wind Event
Sunday August 28, 2011

Tropical Storm Irene making landfall at New York City, image courtesy of NOAA
Tropical Storm Irene making landfall at New York City, image courtesy of NOAA

Tropical storm Irene brought epic flooding of historic proportions to parts of eastern New York and throughout much of Vermont as part of its rampage through the Northeast.  Towns like Margaretville and Fleischmans in eastern Delaware County, Windham, Maplecrest, and Prattsville in Greene County along with all the towns and villages along the Schoharie Creek in Schoharie County, from Gilboa, through Middleburgh, Schoharie, and Esperance, were inundated to levels not seen before.  Entire buildings were wiped out in many of these communities by the violent flash flooding through Sunday August 28 including the total destruction of the Old Blenheim covered bridge, the longest single spanned bridge in the country which was built in 1855.  Countless other towns throughout the Catskills into the Capital Region and mid Hudson valley were also subjected to significant flooding by streams and creeks sent out of their banks by a general range in rainfall from the storm of 4”-8” in twelve to fifteen hours falling throughout the region on an already very wet ground from an unusually wet August.  Locally up to 12” of rain was both estimated by Doppler radar and measured by ground spotters across terrain favored areas of Greene and Ulster counties ultimately leading to the catastrophic floods in the Catskills.  Severe flash flooding also occurred in the Adirondacks, throughout Essex County where the Keene Valley sustained horrendous flood damage. Record flood stages were achieved on the entire length of the Schoharie Creek, on the Mettawee River at Granville, NY, on the Walloomsac River in Bennington, Vt, on the Hudson river at Poughkeepsie, on the Rondout Creek at Rosendale, and on the Canajoharie Creek in Canajoharie. In fact the Walloomsac flood in the Bennington, VT was the worst since the previous record crest was set back on September 21, 1938 when the great 1938 New England Hurricane blasted through the Northeast.

Click here for Flooding and Storm Damage Photographs, Page 1

Click here for Flooding and Storm Damage Photographs, Page 2

Click here for Flooding and Storm Damage Photographs, Page 3  

Photographer: Jim Hamilton, Severe Flooding at Route 143 and 156 in Berne, Sunday August 28, 2011

Photographer: WeatherNet 6 spotter Steve Meicht: Flooding of the Catskill Creek in Catskill Sunday afternoon August 28, 2011
Severe Flooding at Rt. 443 and 156 in Berne, Albany County, Sunday August 28, 2011  Significant Flooding of the Catskill Creek in Catskill, Greene County, Sunday Afternoon August 28, 2011 

Throughout Vermont, every river and stream flooded violently leaving many bridges and roads heavily damaged or destroyed statewide.  According to Vermont Governor Peter Shumlin, hundreds of roads across the state were closed during the storm with three historic covered bridges lost. The flooding in Vermont was declared the most widespread and severe in a century with preliminary federal estimates of seven hundred homes either severely damaged or destroyed.

In the wake of Irene and with the flash floods quickly receding, the massive runoff hit the big rivers early Monday morning August 29.  Both the Mohawk and the Hudson caused serious inundations as the rivers went into flood.  Along the Mohawk, severe flooding occurred from Fonda through Amsterdam and into Rotterdam Junction and Schenectady.  Although, not the record flood that was initially feared Sunday evening, the flooding on the Mohawk was substantial closing the thruway and taking out the historic Guy Park Manor in Amsterdam.  In Schenectady the Stockade flooded with water up to the roof at Jumpin’ Jacks bringing a premature end to their summer season.  Along the Hudson significant flooding occurred from Mechanicville through Waterford, Troy down to Albany.  Several ramps to 787 through Monday August 29 in Albany were closed due to flooding.

Click here for a Summary of the Local River Crests and Hydrograph of the Schoharie Creek at the Gilboa Dam

Figure #1: Albany Doppler Weather Radar Irene Storm Total Rainfall Estimate: The small area of purple and white shaded areas in Greene County indicates a radar estimate of up to 12" of storm total rainfall with the large area in red on the map indicating rainfall anywhere from 5" to 8". The widespread area of orange shading indicates rainfall amounts of 3" to 5". The Doppler estimates are consistent with ground truth spotter reports.

Albany Dopple Weather Radar Irene Storm Total Rainfall Estimate 

Click here for a listing of National Weather Service Cooperative Observer Rainfall Reports

WEATHERNET 6 IRENE STORM TOTAL RAINFALL REPORTS
From Saturday Afternoon through Sunday Night

County

Town

Storm Total Rainfall Report

Litchfield

Sharon, CT

4.77”

 

 

 

Berkshire

Clarksburg, MA

6.00”

Berkshire

Pittsfield, MA

2.70”

Berkshire

Alford, MA

9.00”

Berkshire

Savoy, MA

9.00”

Berkshire

Lanesborough, MA

2.60”

Berkshire

Hancock, MA

6.70”

 

 

 

Albany

Colonie

4.67”

Albany

Cohoes

4.83”

Albany

Glenmont

9.55”

Albany

Green Island

5.20”

Albany

Medusa

5.61”

Albany

East Berne

10.50”

Albany

Cohoes

4.20”

Albany

Latham

3.96”

 

 

 

Columbia

Ghent

6.90”

Columbia

Kinderhook

6.67”

Columbia

Hudson

7.05”

Columbia

Ancramdale

4.72”

Columbia

Chatham Center

6.90”

Columbia

Germantown

5.25”

Columbia

Livingston

8.26”

Columbia

Kinderhook

6.50”

Columbia

Taghkanic

6.51”

Columbia

North Chatham

4.54”

 

 

 

Dutchess

Hopewell Junction

5.65”

Dutchess

Rhinebeck

9.52”

 

 

 

Fulton

Fish House

3.51”

Fulton

Northville

3.15”

Fulton

Broadalbin

3.22”

Fulton

Broadalbin

3.43”

Fulton

Broadalbin

4.76”

 

 

 

Greene

Greenville

5.15”

Greene

Round Top

9.85”

 

 

 

Hamilton

Indian Lake

4.13”

 

 

 

Montgomery

Amsterdam

3.68”

Montgomery

Fonda

3.35”

Montgomery

Glen

3.93”

Montgomery

Stone Ridge

5.80”

Montgomery

Glen

4.12”

Montgomery

Palatine Bridge

2.85”

Montgomery

Fonda

3.80”

Montgomery

Hessville

6.45”

 

 

 

Otsego

Oneonta

3.50”

Otsego

E. Worcester

6.12”

Otsego

Worcester

4.22”

 

 

 

Rensselaer

Center Brunswick

5.58”

Rensselaer

Berlin

6.23”

Rensselaer

Stephentown

5.30”

Rensselaer

Speigletown

4.30”

Rensselaer

Lansingburgh

4.45”

 

 

 

Saratoga

Mechanicville

3.04”

Saratoga

Corinth

2.94”

Saratoga

Malta

3.85”

Saratoga

Milton

3.66”

Saratoga

Ballston Spa

3.93”

Saratoga

Wilton

6.49”

Saratoga

Saratoga Springs

4.43”

Saratoga

Vischer Ferry

3.90”

Saratoga

Clifton

4.55”

 

 

 

Schenectady

Princetown

4.70”

Schenectady

Scotia

5.90”

Schenectady

Duanesburg

6.00”

 

 

 

Schoharie

Richmondville

5.85”

Schoharie

Charlotteville

5.50”

Schoharie

Jefferson

4.60”

Schoharie

Summit

8.88”

Schoharie

Middleburgh

6.04”

Schoharie

Schoharie

8.50”

Schoharie

Fulton

5.40”

 

 

 

Ulster

Kingston

6.77”

Ulster

Kerhonkson

6.70”

 

 

 

Warren

Lake Luzerne

3.97”

Warren

Warrensburg

4.50”

Warren

Queensbury

3.80”

Warren

Queensbury

5.56”

 

 

 

Washington

Eagle Bridge

4.31”

Washington

Cossayuna

4.76”

Washington

Ft. Edward

4.13”

Washington

Salem

5.00”

Washington

Salem

4.05”

 

 

 

Bennington

Landgrove, VT

6.02”

Bennington

Woodford, VT

6.58”

 

 

 

Rutland

West Rutland, VT

7.10”

Rutland

East Wallingford, VT

5.50”

Rutland

Danby, VT

4.36”

The Wind
Roughly seventeen consecutive hours of tropical storm force wind gusts blasted eastern New York and western New England from approximately 5am through 11pm on the 28th.  Measured wind gusts of 50-55 mph were common with winds likely gusting up to 65 mph across the higher elevations and in convective bursts from time to time through the duration of the storm especially across New York and Vermont where the steadiest and heaviest rain occurred for the longest period of time. Significant damage to trees and power lines occurred as the saturated ground conditions allowed for more trees than typical to be blown down.  Vermont power officials estimated that 50,000 customers lost electricity and in the CB6 coverage area, according to National Grid, approximately 150,000 had the lights go out during the storm with significant outages still in progress on Friday September 2, five days after the storm, mainly in areas heavily impacted by flooding where safety concerns regarding turning the juice back on came into play.

There were two wind peaks across the region with Irene. The first occurred early in the storm from the pre-dawn hours through noon when the wind direction was NE to N, a flow which was induced by the strong pressure drop being caused by Irene tracking in from the south. The upper Hudson valley and Capital Region bore the brunt of the first wind maximum during the morning as the Hudson valley effectively channeled, and thus increased the northerly flow, producing stronger wind gusts. Winds dropped for a bit during the early to mid afternoon as the center of Irene passed over western New England but then shifted into the west as the storm center departed during the late afternoon. The combination of the westerly wind shift and the surface pressures rising rapidly with the center of Irene moving away from the region created a favorable scenario for a second period of strong wind gusts, as strong if not stronger than the wind during the morning, in especially the Mohawk valley and Capital Region where the Mohawk valley channeled and thus increased the westerly flow, much like the Hudson valley did during the morning when the flow was northerly. Winds finally began abating between 11pm on the 28th and 1am on the 29th as Irene's center tracked into Canada while filling. The table below lists the weather observations for Albany through the day. Note the pressure drops and rises with the approach and passage of the storm as well as the sustained wind speeds. (Note: The barometric pressure around 2pm at Albany dropped to 28.89" which set the lowest pressure on record at Albany in the month of August. This record low pressure occurred when the center of Irene was located approximately 60 miles east of Albany)

Albany Weather Observations Sunday August 28, 2011

Time
Temperature
Dewpoint
Pressure
Sustained Wind
Midnight 71.1° 69.1° 29.76" NE 5 mph
1 am 71.1° 69.1° 29.74" NNE 8 mph
2 am 70.0° 68.0° 29.71" NNE 9 mph
3 am 68.0° 66.0° 29.63" N 14 mph
4 am 68.0° 66.0° 29.55" N 20 mph
5 am 66.9° 66.0° 29.52" N 20 mph
6 am 66.0° 64.0° 29.46" NNE 23 mph
7 am 66.0° 64.0° 29.37" NNE 23 mph
8 am 66.0° 64.0° 29.25" NNE 31 mph
9 am 64.0° 64.0° 29.15" N 30 mph
10 am 66.0° 64.0° 29.13" NNE 25 mph
11 am 66.0° 64.0° 29.06" NNE 26 mph
Noon 66.0° 64.0° 28.97" NNE 24 mph
1 pm 66.9° 64.9° 28.93" N 22 mph
2 pm 66.0° 64.0° 28.90" N 20 mph
3 pm 66.0° 64.0° 28.93" NNW 17 mph
4 pm 66.0° 64.0° 29.00" WNW 17 mph
5 pm 64.0° 62.0° 29.11" WNW 22 mph
6 pm 64.0° 60.0° 29.19" W 24 mph
7 pm 63.0° 59.0° 29.24" WNW 28 mph
8 pm 63.0° 55.9° 29.35" W 33 mph
9 pm 61.0° 55.0° 29.45" W 31 mph
10 pm 61.0° 55.0° 29.53" W 32 mph
11 pm 61.0° 52.0° 29.57" WNW 24 mph
Midnight 60.1° 52.0° 29.64" WNW 22 mph

Click Here for a Listing of Peak Wind Gust Reports

Photographer: Tom Boardman:, Tree down on a home in Bethlehem, Albany County, Sunday August 28, 2011

Photographer: Diane Summers Ashloy: A large uprooted tree in Jefferson Heights, Greene County, August 28, 2011
Tree on a home in Bethlehem, NY, Albany County Sunday August 28, 2011  Uprooted tree in Jefferson Heights, Greene County, Sunday August 28, 2011 

Damage Estimates
Early estimates on the damage from the storm in New York alone, according to Governor Cuomo’s office, had the figure conservatively at one billion dollars with six hundred homes completely destroyed, one hundred fifty roads closed along with twenty two bridges severely damaged.  In the CBS6 coverage area, Albany, Columbia, Delaware, Dutchess, Greene, Montgomery, Rensselaer, Saratoga, Schenectady, Schoharie, Ulster, Washington, and Warren counties were declared Federal Disaster areas making federal funds available to individuals directly impacted by the destruction from Irene.

Click Here for the National Weather Service Local Storm Report Summary

Irene’s Track

Graphic from the National Oceanic and Atmospheric Administration (NOAA)
Irene's Track, Graphic Courtesy of NOAA


Saturday August 20:
Irene was named a tropical storm just east of the northern Leeward islands early in the day on the 20th.

Sunday August 21:
The system moved across the northern Leeward's as a tropical storm through the morning of the 21st producing locally heavy rain and squally weather

Monday August 22:
By 6am on the 22nd, Irene had become a minimal category 1 75 mph hurricane and was positioned 40 miles WNW of San Juan Puerto Rico.

Tuesday August 23:
Irene moved from near Puerto Rico on a track that would have it shirt the north shore of the Dominican Republic as a 100 mph hurricane.  By 11pm on the 23rd, Irene was making its approach on the Turks and Caicos Islands on a track that would have it plowing through the heart of the Bahamas.

Wednesday-Friday August 24-26:
Irene peaked out at a category 3 120 mph hurricane as of the 11pm National Hurricane Center update on its approach to the northwestern Bahamas on the 24th.  By 11pm on the 25th, winds with Irene were still a respectable 115 mph as it took aim on eastern North Carolina. Through Friday the 26th Irene made steady progress towards North Carolina, undergoing some weakening as dry air entrained into the circulation.

Saturday August 27:
Irene made landfall at Cape Lookout at approximately 8am on the 27th with top sustained winds of 85 mph, lower due in part to the slug of dry air which wrapped into the circulation along with increased shear as it moved along the coast. 

Sunday August 28:
From North Carolina's outer banks, the storm remained on a steady state track that would take it up along the New Jersey coast and into New York City where it made landfall at approximately 9am Sunday August 28 as a 65 mph Tropical Storm.  Irene, moving faster at this point, NNE at 26 mph, continued to the northeast moving up through western Litchfield County, CT to a position fifteen miles south of Pittsfield, MA in Berkshire County at 2pm on the 28th with winds of 60 mph.  By 5pm, winds were down to 50 mph with a position sixty five miles south of Rutland, VT. The National Hurricane Center issued the last advisory on Irene at 11pm on the 28th as the storm transitioned to post tropical as it was moving to the N. H.-Canada border.

Irene’s course took it on a fairly typical track up through the Bahamas to extreme eastern North Carolina.  Many tropical system have taken this track in the past as they are steered around the western periphery of the subtropical ridge commonly located over the central Atlantic in August and September.  Often, however, tropical systems will continue to re curve prior to reaching the Northeast as there is typically a weakness on the top of the ridge and/or the system hits a trough of low pressure in the prevailing westerlies at higher latitudes which will pick them up and kick them east and out to sea.  In this case, however, the ocean ridge at the steering level was quite strong and situated further west than typical.  And the low pressure trough in the westerlies was located west of the New York and New England setting up a south to southwest flow from the Carolinas through the Northeast at the steering level.  The combined flows between the jet stream trough and the blocking offshore subtropical ridge provided a narrow channel for Irene to follow taking it on the steady state course through western New England.

Irene was a large storm spatially, spanning some 400 miles in diameter. It was also a strong system based on its very low barometric pressure which it maintained despite the considerable weakening of the surface winds. As the storm weakened further on its northward journey into the Northeast it loosened up, with the wind fields spreading out over a larger area and generally being enhanced by momentum mix downs in heavier bursts of rain and thunderstorms, rather than the wind being concentrated in a ring around the center, as is the case in a well structured tropical system. Irene was not a well structured tropical system when it arrived in New York and western New England, lacking any real core of strong convection around the center. However, one could argue, that as the center of the storm made its way into western New England, that a pseudo eye wall type feature did set up over the Hudson valley during the early afternoon as radar indicated a line of intense rainfall with occasional bursts of lightning which developed on the western side of the circulation. Very heavy rainfall ensued along and just west of the Hudson river in eastern Greene, western Columbia, eastern Albany, western Rensselaer, and southern Washington counties for one to two hours with this band of rain. While this was occurring, a significant mass of dry air had wrapped around the southern and eastern side of the circulation so as Irene moved up through Berkshire County through the mid afternoon, drying quickly followed with the steadiest and heaviest rainfall shutting down from south to north through the evening hours. Bands of lighter rain continued in especially the Mohawk valley and Capital Region through 9pm before tapering off and ending just prior to midnight.