Severe thunderstorms produced intense winds and large hail across Adams, Broomfield, Douglas, Jefferson, Morgan, Weld and Phillips counties.  The hail ranged in size from one to two inches in diameter.  Three short-lived brief tornadoes touched down in Phillips County.  One caused moderate damage, when it destroyed two outbuildings and rolled over a semi-trailer.  Very heavy rainfall in southeast Phillips County, caused flash flooding the forced closures of US 6 east of Holyoke and several other county roads southeast of town.

Flash Flood in PHILLIPS, COLORADO
From 19-AUG-21 18:07:00 to 20-AUG-21 02:00:00 (MST-7)
Location: HOLYOKE
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 25.00K
Reported by: Emergency Manager

Thunderstorms produced very heavy rain in southeast Phillips County.  Local law enforcement reported several roads were flooded southeast of Holyoke.  Rainfall measurements from 4 to 9 inches were reported.  Several houses had water rise up to the front doors.  Significant flash flooding was observed 6 miles east of Holyoke on U.S. Highway 6.  Widespread flooding of roads, ditches, and fields was reported. At least one road crossing Frenchman Creek was impassable.  Frenchman Creek and other streams had significant flooding as well.

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:45:00 to 19-AUG-21 13:45:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.25 
Reported by: Trained Spotter

Tornado in PHILLIPS, COLORADO
From 19-AUG-21 16:20:00 to 19-AUG-21 16:30:00 (MST-7)
Location: HOLYOKE ARPT
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A weak tornado touched down in an open field, but no damage was reported.

Tornado in PHILLIPS, COLORADO
From 19-AUG-21 16:09:00 to 19-AUG-21 16:10:00 (MST-7)
Location: HOLYOKE ARPT
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

A tornado touched down briefly in an open field.  No damage was observed.

Tornado in PHILLIPS, COLORADO
From 19-AUG-21 16:07:00 to 19-AUG-21 16:12:00 (MST-7)
Location: HOLYOKE ARPT
Tornado F-scale: EF1
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Public

A tornado touched down and destroyed two outbuildings.  It also rolled a semi trailer.

Thunderstorm Wind in PHILLIPS, COLORADO
From 19-AUG-21 16:22:00 to 19-AUG-21 16:22:00 (MST-7)
Location: HOLYOKE ARPT
Magnitude: 57.00 MG
Reported by: ASOS

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:25:00 to 19-AUG-21 13:25:00 (MST-7)
Location: GOLDEN
Magnitude: 2.00 
Reported by: Public

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:28:00 to 19-AUG-21 13:28:00 (MST-7)
Location: ARVADA
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:29:00 to 19-AUG-21 13:29:00 (MST-7)
Location: GOLDEN
Magnitude: 1.50 
Reported by: Public

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:40:00 to 19-AUG-21 13:40:00 (MST-7)
Location: JEFFERSON CO ARPT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:40:00 to 19-AUG-21 13:40:00 (MST-7)
Location: ARVADA
Magnitude: 1.00 
Reported by: Public

Hail in DOUGLAS, COLORADO
From 19-AUG-21 13:33:00 to 19-AUG-21 13:33:00 (MST-7)
Location: CASTLE ROCK
Magnitude: 1.00 
Reported by: Public

Hail in DOUGLAS, COLORADO
From 19-AUG-21 13:40:00 to 19-AUG-21 13:40:00 (MST-7)
Location: FRANKTOWN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:45:00 to 19-AUG-21 13:45:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.50 
Reported by: Public

Hail in ADAMS, COLORADO
From 19-AUG-21 13:53:00 to 19-AUG-21 13:53:00 (MST-7)
Location: NORTHGLENN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in BROOMFIELD, COLORADO
From 19-AUG-21 13:53:00 to 19-AUG-21 13:53:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.00 
Reported by: Public

Hail in BROOMFIELD, COLORADO
From 19-AUG-21 13:50:00 to 19-AUG-21 13:50:00 (MST-7)
Location: BROOMFIELD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in ADAMS, COLORADO
From 19-AUG-21 13:50:00 to 19-AUG-21 13:50:00 (MST-7)
Location: FEDERAL HGT
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:49:00 to 19-AUG-21 13:49:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.00 
Reported by: Public

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:48:00 to 19-AUG-21 13:48:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.00 
Reported by: Public

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:47:00 to 19-AUG-21 13:47:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.00 
Reported by: NWS Employee

Hail in ADAMS, COLORADO
From 19-AUG-21 14:09:00 to 19-AUG-21 14:09:00 (MST-7)
Location: HENDERSON
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ADAMS, COLORADO
From 19-AUG-21 14:06:00 to 19-AUG-21 14:06:00 (MST-7)
Location: NORTHGLENN
Magnitude: 1.00 
Reported by: Public

Hail in ADAMS, COLORADO
From 19-AUG-21 13:45:00 to 19-AUG-21 13:45:00 (MST-7)
Location: FEDERAL HGT
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in DOUGLAS, COLORADO
From 19-AUG-21 13:42:00 to 19-AUG-21 13:42:00 (MST-7)
Location: CASTLE ROCK
Magnitude: 0.88 
Reported by: Broadcast Media

Hail in DOUGLAS, COLORADO
From 19-AUG-21 14:51:00 to 19-AUG-21 14:51:00 (MST-7)
Location: PARKER
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DOUGLAS, COLORADO
From 19-AUG-21 14:40:00 to 19-AUG-21 14:40:00 (MST-7)
Location: PARKER
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in DOUGLAS, COLORADO
From 19-AUG-21 14:19:00 to 19-AUG-21 14:19:00 (MST-7)
Location: CASTLE ROCK
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in ADAMS, COLORADO
From 19-AUG-21 13:50:00 to 19-AUG-21 13:50:00 (MST-7)
Location: FEDERAL HGT
Magnitude: 1.25 
Reported by: Trained Spotter

Hail in ADAMS, COLORADO
From 19-AUG-21 13:50:00 to 19-AUG-21 13:50:00 (MST-7)
Location: FEDERAL HGT
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:50:00 to 19-AUG-21 13:50:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.25 
Reported by: Public

Hail in DOUGLAS, COLORADO
From 19-AUG-21 13:30:00 to 19-AUG-21 13:30:00 (MST-7)
Location: CASTLE ROCK
Magnitude: 1.00 
Reported by: Trained Spotter

Hail in WELD, COLORADO
From 19-AUG-21 15:06:00 to 19-AUG-21 15:06:00 (MST-7)
Location: MASTERS
Magnitude: 0.88 
Reported by: Trained Spotter

Hail in ADAMS, COLORADO
From 19-AUG-21 15:02:00 to 19-AUG-21 15:02:00 (MST-7)
Location: BENNETT
Magnitude: 1.50 
Reported by: Public

Hail in DOUGLAS, COLORADO
From 19-AUG-21 14:45:00 to 19-AUG-21 14:45:00 (MST-7)
Location: THE PINERY
Magnitude: 1.00 
Reported by: Public

Hail in MORGAN, COLORADO
From 19-AUG-21 15:19:00 to 19-AUG-21 15:19:00 (MST-7)
Location: ORCHARD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in JEFFERSON, COLORADO
From 19-AUG-21 13:46:00 to 19-AUG-21 13:46:00 (MST-7)
Location: BROOMFIELD
Magnitude: 1.50 
Reported by: Trained Spotter

Hail in ADAMS, COLORADO
From 19-AUG-21 15:05:00 to 19-AUG-21 15:05:00 (MST-7)
Location: BENNETT
Magnitude: 1.25 
Reported by: Public

Hail in WELD, COLORADO
From 19-AUG-21 14:30:00 to 19-AUG-21 14:30:00 (MST-7)
Location: ROGGEN
Magnitude: 1.50 
Reported by: Storm Chaser