A west-east oriented cold front crawled south across the North Country, at the time of maximum heating and instability, during the afternoon and evening hours of July 17th. Along this frontal boundary were a series of weak areas of low pressure. This resulted in numerous thunderstorms in New York with damaging winds, especially in portions of St. Lawrence county, where the community of Potsdam and vicinity were particularly hard hit.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 15:36:00 to 17-JUL-12 15:38:00 (EST-5)
Location: ELIZABETHTOWN
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous trees down.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 15:54:00 to 17-JUL-12 15:55:00 (EST-5)
Location: WESTPORT
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Employee

Multiple trees down along Lakeshore Drive.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 15:54:00 to 17-JUL-12 15:54:00 (EST-5)
Location: WADHAMS
Magnitude: 50.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: NWS Employee

Large tree down across house.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 15:05:00 to 17-JUL-12 15:05:00 (EST-5)
Location: BLOOMINGDALE
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

Multiple trees and power lines down.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 15:30:00 to 17-JUL-12 15:30:00 (EST-5)
Location: WILLSBORO
Magnitude: 50.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Public

Damage to Willsboro Bay Marina as well as several large trees.

Thunderstorm Wind in CLINTON, NEW YORK
From 17-JUL-12 14:50:00 to 17-JUL-12 14:50:00 (EST-5)
Location: SARANAC
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Several trees down.

Thunderstorm Wind in CLINTON, NEW YORK
From 17-JUL-12 14:49:00 to 17-JUL-12 14:49:00 (EST-5)
Location: REDFORD
Magnitude: 50.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Public

Uprooted trees and damage to siding of a house.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 16:30:00 to 17-JUL-12 16:30:00 (EST-5)
Location: SCHROON LAKE
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple trees down in Schroon Lake.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 16:24:00 to 17-JUL-12 16:24:00 (EST-5)
Location: NORTH HUDSON ARPT
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Several trees down.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 16:25:00 to 17-JUL-12 16:25:00 (EST-5)
Location: SEVERANCE
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous trees down along with some power lines.

Lightning in ESSEX, NEW YORK
From 17-JUL-12 15:40:00 to 17-JUL-12 15:40:00 (EST-5)
Location: LEWIS
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A few structure fires in Essex county due to lightning, including a house in Lewis.

Thunderstorm Wind in ST. LAWRENCE, NEW YORK
From 17-JUL-12 14:25:00 to 17-JUL-12 14:25:00 (EST-5)
Location: FT JACKSON
Magnitude: 50.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple trees and power lines down.

Thunderstorm Wind in ST. LAWRENCE, NEW YORK
From 17-JUL-12 15:00:00 to 17-JUL-12 15:00:00 (EST-5)
Location: RUSSELL
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Several trees down.

Thunderstorm Wind in FRANKLIN, NEW YORK
From 17-JUL-12 15:08:00 to 17-JUL-12 15:09:00 (EST-5)
Location: SARANAC LAKE
Magnitude: 50.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Multiple trees and power lines down across the Saranac Lake community.

Thunderstorm Wind in FRANKLIN, NEW YORK
From 17-JUL-12 15:05:00 to 17-JUL-12 15:05:00 (EST-5)
Location: PAUL SMITHS
Magnitude: 50.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Multiple trees down forcing closure on Route 30.

Hail in ST. LAWRENCE, NEW YORK
From 17-JUL-12 14:21:00 to 17-JUL-12 14:21:00 (EST-5)
Location: POTSDAM
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Nickel size hail reported.

Hail in ST. LAWRENCE, NEW YORK
From 17-JUL-12 14:40:00 to 17-JUL-12 14:40:00 (EST-5)
Location: WINTHROP
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Penny size hail reported.

Hail in ST. LAWRENCE, NEW YORK
From 17-JUL-12 15:45:00 to 17-JUL-12 15:45:00 (EST-5)
Location: EDWARDS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

One inch diameter hail reported via SHAVE experiment.

Hail in ST. LAWRENCE, NEW YORK
From 17-JUL-12 17:00:00 to 17-JUL-12 17:00:00 (EST-5)
Location: CRANBERRY LAKE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Quarter size hail reported.

Thunderstorm Wind in ST. LAWRENCE, NEW YORK
From 17-JUL-12 14:21:00 to 17-JUL-12 14:25:00 (EST-5)
Location: POTSDAM
Magnitude: 65.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Public

Multiple trees down and snapped and power lines down across Potsdam with structural damage to 4 buildings forcing dozens of evacuations.

Thunderstorm Wind in ST. LAWRENCE, NEW YORK
From 17-JUL-12 14:28:00 to 17-JUL-12 14:30:00 (EST-5)
Location: COLTON
Magnitude: 55.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Numerous trees down with power lines as well.

Thunderstorm Wind in ST. LAWRENCE, NEW YORK
From 17-JUL-12 14:30:00 to 17-JUL-12 14:32:00 (EST-5)
Location: HANNAWA FALLS
Magnitude: 60.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Multiple trees uprooted and snapped with estimated winds by local police of 60 knots.

Thunderstorm Wind in ESSEX, NEW YORK
From 17-JUL-12 15:30:00 to 17-JUL-12 15:30:00 (EST-5)
Location: WILLSBORO PT
Magnitude: 50.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

Multiple trees and large branches downed by thunderstorm winds.

Hail in ST. LAWRENCE, NEW YORK
From 17-JUL-12 15:35:00 to 17-JUL-12 15:35:00 (EST-5)
Location: EDWARDS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

One inch diameter hail reported via SHAVE experiment.