Scattered thunderstorms developed in a moderately unstable airmass across the Champlain Valley of New York during the afternoon of the 16th. One thunderstorm developed in a favorable, highly sheared wind environment which eventually intensified into a supercell thunderstorm across Clinton county, NY. This supercell thunderstorm moved across the New York locations of Jericho, Keesville, northern Plattsburgh and Cumberlandhead, before heading into Lake Champlain and eventually Vermont. Significant straight-line wind damage (estimated between 60 and 80 mph) in the form of snapped, uprooted and downed trees, downed power lines and structural damage such as trees on houses as well as roof shingles and siding blown off. Also, several boats and docks were damaged in local marina. Large hail was also reported.

Thunderstorm Wind in ST. LAWRENCE, NEW YORK
From 16-AUG-07 14:30:00 to 16-AUG-07 14:30:00 (EST-5)
Location: MASSENA
Magnitude: 50.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Utility Company

Large plate glass window blown in at Robert Moses Power Dam administrative building. Also, trees down in Robert Moses State park.

Thunderstorm Wind in CLINTON, NEW YORK
From 16-AUG-07 14:30:00 to 16-AUG-07 14:30:00 (EST-5)
Location: ALTONA
Magnitude: 50.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Department of Highways

Numerous trees down in the town of Altona, including on Alberbeen road.

Thunderstorm Wind in CLINTON, NEW YORK
From 16-AUG-07 14:40:00 to 16-AUG-07 14:40:00 (EST-5)
Location: BEEKMANTOWN
Magnitude: 60.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several dozen trees reported downed by thunderstorm winds in Beekmantown. A tractor-trailer was blown over and suffered damage near mile marker 159 on Interstate 87.

Hail in CLINTON, NEW YORK
From 16-AUG-07 14:35:00 to 16-AUG-07 14:35:00 (EST-5)
Location: WEST BEEKMANTOWN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nickel size hail was reported in Plattsburgh, NY. In addition, small branches on trees were blown down.

Thunderstorm Wind in CLINTON, NEW YORK
From 16-AUG-07 14:45:00 to 16-AUG-07 14:45:00 (EST-5)
Location: PLATTSBURGH
Magnitude: 60.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Trees down, wind gusts estimated to 70 mph and quarter size hail reported (and videotaped) by local television station situated along Route 9 about  1 mile north-northeast of Plattsburgh.

Thunderstorm Wind in CLINTON, NEW YORK
From 16-AUG-07 14:45:00 to 16-AUG-07 14:45:00 (EST-5)
Location: PLATTSBURGH
Magnitude: 70.00 EG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous trees down...damaged roofs and power poles across North Plattsburgh and East Beekmantown including Moffitt, Pardy roads and State Route 9.

Thunderstorm Wind in CLINTON, NEW YORK
From 16-AUG-07 14:45:00 to 16-AUG-07 14:45:00 (EST-5)
Location: PLATTSBURGH
Magnitude: 70.00 EG
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous trees downed by thunderstorm winds across Cumberland Head and local state park as well as damaged docks and boats at the Treadwell marina. Several trees and large branches fell on camp sites within state park with only a few minor injuries reported.

Hail in CLINTON, NEW YORK
From 16-AUG-07 14:40:00 to 16-AUG-07 14:40:00 (EST-5)
Location: BEEKMANTOWN
Magnitude: 1.75 
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Numerous reports of large hail ranging from Quarter size to Golf ball size. Large hail resulted in several broken car windshields, dented vehicles and a few house windows broken.

Hail in CLINTON, NEW YORK
From 16-AUG-07 14:45:00 to 16-AUG-07 14:45:00 (EST-5)
Location: PLATTSBURGH
Magnitude: 0.88 
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Public

Nickel size hail and estimated 60 mph or higher wind gusts with numerous branches knocked down reported and videotaped by local television station.

Thunderstorm Wind in CLINTON, NEW YORK
From 16-AUG-07 14:30:00 to 16-AUG-07 14:30:00 (EST-5)
Location: DANNEMORA
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Department of Highways

Tree downed by thunderstorm winds across pickup truck.