A severe thunderstorm produced damaging winds, large hail and very heavy rain across the western and southern suburbs of Denver.  Widespread damage was observed in the cities of Arvada, Wheat Ridge and Lakewood.  The intense straightline winds were the result of a wet microburst which downed hundreds of trees and snapped power poles.  Winds gusts to 80 mph were reported along with nickel to golfball size hail.  The combination of wind and hail produced widepread damage to homes and vehicles.  The damage claim estimates totaled $350 million; about 32,900 claims were filed for homes, while another 19,500 claims were for vehicles.  As many as 90,000 homes and businesses were left without power.  In some areas it took up to 3 days to completely restore electrical service.  Minor injuries were reported from broken glass during the storm, but no one was hospitalized.   The storm crippled the computers at the Colorado Crime Information Center in Lakewood for nearly 3 hours.  One weak tornado was also observed.
In Larimer and Weld Counties, severe thunderstorms produced widepread damage over approximately 150 square miles of farmland.  In all, 400 farms were directly impacted by severe weather.  Damage to crops alone was estimated to be around $4 million; most of the damage was observed in Weld County.

Thunderstorm Wind in JEFFERSON, COLORADO
From 20-JUL-09 21:15:00 to 20-JUL-09 21:15:00 (MST-7)
Location: ARVADA
Magnitude: 60.00 MG
Reported by: NWS Employee

Thunderstorm Wind in JEFFERSON, COLORADO
From 20-JUL-09 21:15:00 to 20-JUL-09 21:15:00 (MST-7)
Location: ARVADA
Magnitude: 60.00 MG
Reported by: NWS Employee

Hail in WELD, COLORADO
From 20-JUL-09 21:01:00 to 20-JUL-09 21:01:00 (MST-7)
Location: FIRESTONE
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in LARIMER, COLORADO
From 20-JUL-09 21:05:00 to 20-JUL-09 21:05:00 (MST-7)
Location: MOUNTAIN VIEW
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:10:00 to 20-JUL-09 21:10:00 (MST-7)
Location: ARVADA
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BROOMFIELD, COLORADO
From 20-JUL-09 21:25:00 to 20-JUL-09 21:25:00 (MST-7)
Location: BROOMFIELD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:22:00 to 20-JUL-09 21:22:00 (MST-7)
Location: ARVADA
Magnitude: 1.00 
Reported by: NWS Employee

Hail in WELD, COLORADO
From 20-JUL-09 21:10:00 to 20-JUL-09 21:10:00 (MST-7)
Location: PLATTEVILLE
Magnitude: 2.00 
Crop damage: 3.00M
Reported by: Newspaper

Two separate storms moved across Miller Farm, near State Highway 66 and County Road 19, and caused widespread crop damage.  Approximately 200 acres of the farm was devastated by strong winds, heavy rain and hail.  In all, 400 farms were directly impacted by the storms with widespread crop damage across Larimer and Weld Counties.

Hail in DOUGLAS, COLORADO
From 20-JUL-09 22:20:00 to 20-JUL-09 22:20:00 (MST-7)
Location: TOMAH
Magnitude: 1.00 
Reported by: Trained Spotter

Thunderstorm Wind in WELD, COLORADO
From 20-JUL-09 22:15:00 to 20-JUL-09 22:15:00 (MST-7)
Location: FT LUPTON
Magnitude: 58.00 MG
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:28:00 to 20-JUL-09 21:28:00 (MST-7)
Location: LAKEWOOD
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:26:00 to 20-JUL-09 21:26:00 (MST-7)
Location: LAKEWOOD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LARIMER, COLORADO
From 20-JUL-09 21:18:00 to 20-JUL-09 21:18:00 (MST-7)
Location: LOVELAND
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in LARIMER, COLORADO
From 20-JUL-09 21:16:00 to 20-JUL-09 21:16:00 (MST-7)
Location: DRAKES
Magnitude: 1.75 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:38:00 to 20-JUL-09 21:38:00 (MST-7)
Location: ARVADA
Magnitude: 1.00 
Reported by: NWS Employee

Hail in LARIMER, COLORADO
From 20-JUL-09 21:37:00 to 20-JUL-09 21:37:00 (MST-7)
Location: DRAKES
Magnitude: 2.00 
Crop damage: 1.00M
Reported by: Trained Spotter

Hail in LARIMER, COLORADO
From 20-JUL-09 21:17:00 to 20-JUL-09 21:17:00 (MST-7)
Location: HARMONY
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in WELD, COLORADO
From 20-JUL-09 21:15:00 to 20-JUL-09 21:15:00 (MST-7)
Location: FT LUPTON
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 22:00:00 to 20-JUL-09 22:00:00 (MST-7)
Location: EDGEWATER
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:18:00 to 20-JUL-09 21:18:00 (MST-7)
Location: GOLDEN
Magnitude: 1.00 
Reported by: NWS Employee

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:18:00 to 20-JUL-09 21:18:00 (MST-7)
Location: ARVADA
Magnitude: 1.25 
Reported by: NWS Employee

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:45:00 to 20-JUL-09 21:45:00 (MST-7)
Location: COLUMBINE
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 20-JUL-09 21:15:00 to 20-JUL-09 21:15:00 (MST-7)
Location: COLUMBINE
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in WELD, COLORADO
From 20-JUL-09 21:12:00 to 20-JUL-09 21:12:00 (MST-7)
Location: FT LUPTON
Magnitude: 2.00 
Reported by: Trained Spotter

Tornado in DOUGLAS, COLORADO
From 20-JUL-09 22:39:00 to 20-JUL-09 22:39:00 (MST-7)
Location: CASTLE ROCK
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A tornado touched down but did no damage.

Hail in JEFFERSON, COLORADO
From 20-JUL-09 22:12:00 to 20-JUL-09 22:12:00 (MST-7)
Location: COLUMBINE
Magnitude: 1.25 
Property damage: 350.00M
Reported by: Trained Spotter

Thunderstorm Wind in JEFFERSON, COLORADO
From 20-JUL-09 21:30:00 to 20-JUL-09 21:30:00 (MST-7)
Location: JEFFERSON CO ARPT
Magnitude: 52.00 MG
Reported by: Trained Spotter

Thunderstorm Wind in JEFFERSON, COLORADO
From 20-JUL-09 21:15:00 to 20-JUL-09 21:15:00 (MST-7)
Location: LAKEWOOD
Magnitude: 61.00 MG
Reported by: Trained Spotter

Thunderstorm Wind in WELD, COLORADO
From 20-JUL-09 22:27:00 to 20-JUL-09 22:27:00 (MST-7)
Location: TONVILLE
Magnitude: 70.00 MG
Reported by: Trained Spotter

Hail in BROOMFIELD, COLORADO
From 20-JUL-09 21:10:00 to 20-JUL-09 21:10:00 (MST-7)
Location: BROOMFIELD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter