Thunderstorm winds brought down numerous trees, utility poles, power lines and caused structural damage as a derecho crossed the region. There were also numerous reports of dime to nickel sized hail with isolated reports of one to one and a half inch hail over Wyoming and southern Livingston counties. Falling trees damaged buildings in Alden, Erie county, and Lockport and North Tonawanda, Niagara county. The winds caused structural damage in the town of Seneca, Ontario county, Niagara Falls, Niagara county, and Alden and Tonawanda, Erie county.  A large billboard and a large motel sign were blown over in Niagara Falls. Up to 10,000 customers were temporarily left without power by the storm.

Hail in MONROE, NEW YORK
From 18-APR-04 11:30:00 to 18-APR-04 11:30:00 (EST)
Location: FAIRPORT
Magnitude: 0.88 
Property damage: 10K
Reported by: TRAINED SPOTTER

Hail in ONTARIO, NEW YORK
From 18-APR-04 11:40:00 to 18-APR-04 11:40:00 (EST)
Location: SENECA CASTLE
Magnitude: 0.75 
Property damage: 100K
Reported by: LAW ENFORCEMENT

Hail in WAYNE, NEW YORK
From 18-APR-04 11:40:00 to 18-APR-04 11:40:00 (EST)
Location: PALMYRA
Magnitude: 0.75 
Property damage: 25K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in GENESEE, NEW YORK
From 18-APR-04 10:30:00 to 18-APR-04 10:30:00 (EST)
Location: DARIEN
Magnitude: 75 EG
Property damage: 50K
Reported by: NWS STORM SURVEY

Hail in LIVINGSTON, NEW YORK
From 18-APR-04 11:55:00 to 18-APR-04 11:55:00 (EST)
Location: DANSVILLE
Magnitude: 0.75 
Property damage: 10K
Reported by: LAW ENFORCEMENT

Hail in LIVINGSTON, NEW YORK
From 18-APR-04 11:15:00 to 18-APR-04 11:15:00 (EST)
Location: CALEDONIA
Magnitude: 0.75 
Property damage: 15K
Reported by: LAW ENFORCEMENT

Hail in LIVINGSTON, NEW YORK
From 18-APR-04 11:38:00 to 18-APR-04 11:38:00 (EST)
Location: MT MORRIS
Magnitude: 0.75 
Property damage: 15K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ALLEGANY, NEW YORK
From 18-APR-04 12:20:00 to 18-APR-04 12:20:00 (EST)
Location: RUSHFORD
Magnitude: 50 EG
Property damage: 15K
Reported by: LAW ENFORCEMENT

Hail in NIAGARA, NEW YORK
From 18-APR-04 09:55:00 to 18-APR-04 09:55:00 (EST)
Location: NIAGARA FALLS
Magnitude: 0.88 
Property damage: 500K
Reported by: PARK/FOREST SERVICE

Thunderstorm Wind in ERIE, NEW YORK
From 18-APR-04 10:03:00 to 18-APR-04 10:03:00 (EST)
Location: BUFFALO
Magnitude: 55 EG
Property damage: 100K
Reported by: TRAINED SPOTTER

Hail in MONROE, NEW YORK
From 18-APR-04 11:05:00 to 18-APR-04 11:05:00 (EST)
Location: SPENCERPORT
Magnitude: 0.88 
Property damage: 25K
Reported by: LAW ENFORCEMENT

Hail in GENESEE, NEW YORK
From 18-APR-04 10:48:00 to 18-APR-04 10:48:00 (EST)
Location: BATAVIA
Magnitude: 0.75 
Property damage: 50K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in ORLEANS, NEW YORK
From 18-APR-04 10:50:00 to 18-APR-04 10:50:00 (EST)
Location: KENDALL
Magnitude: 60 EG
Property damage: 50K
Reported by: INSURANCE COMPANY

Hail in WYOMING, NEW YORK
From 18-APR-04 10:52:00 to 18-APR-04 10:52:00 (EST)
Location: ATTICA
Magnitude: 0.75 
Property damage: 25K
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ERIE, NEW YORK
From 18-APR-04 10:20:00 to 18-APR-04 10:20:00 (EST)
Location: ALDEN
Magnitude: 75 MG
Property damage: 200K
Reported by: NWS STORM SURVEY