Colorado, 1997

Tornadoes and Flash Flood in Colorado, June 25, 1997

June 25, 1997 · NWS BOU · 21 events in 7 counties and zones

17 hail, 2 tornado, 1 flash flood, 1 thunderstorm wind, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

Open the live radar over this ground

The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
21

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

The radar

The Cheyenne radar (KCYS), 150 km away, was scanning. The volume nearest the first event began at 22:04 UTC.

Open the radar archive at this moment

Event by event

17 hail, 2 tornado, 1 flash flood, 1 thunderstorm wind. Local standard time, as filed.

Flash Flood, Logan

When
June 25, 3:00 PM MST to 5:00 PM MST
Where
Logan County, Sterling
Coordinates
40.725, -103.110 (the zone’s center; the record gives no point)

Thunderstorms with torrential rain and hail flooded the Sterling area during the late afternoon. Two to three inches of rain fell in a 30 minute period. The town was left immobilized as the water was several feet deep in places. Snowplows had to be called to remove hail from Interstate 76.

Tornado, Logan

When
June 25, 3:05 PM MST to 3:10 PM MST
Where
Logan County, 5 mi W of Atwood
Rating
F0
Path length
1 mi
Path width
100 yd
Coordinates
40.550, -103.370

Hail, Sedgwick

When
June 25, 3:14 PM MST
Where
Sedgwick County, 3 mi E of Julesburg
Measured
1 in hail
Coordinates
40.980, -102.220

Hail, Sedgwick

When
June 25, 3:22 PM MST
Where
Sedgwick County, 6 mi S of Julesburg
Measured
1.75 in hail
Coordinates
40.900, -102.270

Tornado, Morgan

When
June 25, 3:50 PM MST
Where
Morgan County, 3 mi SW of Hillrose
Rating
F0
Path length
0.1 mi
Path width
50 yd
Coordinates
40.280, -103.550

Thunderstorm Wind, Boulder

When
June 25, 5:45 PM MST
Where
Boulder County, Longmont
Coordinates
40.170, -105.100

Strong thunderstorm winds downed power lines which caused a 30 minute power outage.

Hail, Boulder

When
June 25, 6:55 PM MST to 7:00 PM MST
Where
Boulder County, Boulder
Measured
1.25 in hail
Coordinates
40.020, -105.270

Hail, Boulder

When
June 25, 7:05 PM MST
Where
Boulder County, Boulder
Measured
0.75 in hail
Coordinates
40.020, -105.270

Hail, Boulder

When
June 25, 7:20 PM MST
Where
Boulder County, Louisville
Measured
0.75 in hail
Coordinates
39.980, -105.130

Hail, Jefferson

When
June 25, 7:20 PM MST
Where
Jefferson County, Arvada
Measured
0.75 in hail
Coordinates
39.800, -105.080

Hail, Jefferson

When
June 25, 7:30 PM MST
Where
Jefferson County, Arvada
Measured
1 in hail
Coordinates
39.800, -105.080

Hail, Jefferson

When
June 25, 7:32 PM MST
Where
Jefferson County, Jefferson Co Arpt
Measured
0.75 in hail
Coordinates
39.900, -105.120

Hail, Jefferson

When
June 25, 7:33 PM MST
Where
Jefferson County, Arvada
Measured
0.75 in hail
Coordinates
39.800, -105.080

Hail, Jefferson

When
June 25, 7:36 PM MST
Where
Jefferson County, 1 mi E of Jefferson Co Arpt
Measured
0.75 in hail
Coordinates
39.900, -105.100

Hail, Adams

When
June 25, 7:37 PM MST
Where
Adams County, Westminster
Measured
0.75 in hail
Coordinates
39.830, -105.030

Hail, Denver

When
June 25, 7:45 PM MST
Where
Denver County, Denver
Measured
0.75 in hail
Coordinates
39.730, -104.930

Hail, Jefferson

When
June 25, 7:49 PM MST
Where
Jefferson County, Arvada
Measured
0.88 in hail
Coordinates
39.800, -105.080

Hail, Boulder

When
June 25, 7:55 PM MST
Where
Boulder County, Longmont
Measured
0.75 in hail
Coordinates
40.170, -105.100

Hail, Boulder

When
June 25, 8:00 PM MST
Where
Boulder County, Longmont
Measured
0.75 in hail
Coordinates
40.170, -105.100

Hail, Boulder

When
June 25, 8:05 PM MST
Where
Boulder County, Longmont Muni Arpt
Measured
1 in hail
Coordinates
40.170, -105.170

Hail, Boulder

When
June 25, 8:06 PM MST
Where
Boulder County, Longmont
Measured
1 in hail
Coordinates
40.170, -105.100

Heavy rain and hail caused widespread street flooding in Longmont. Standing water was 2 feet deep in spots.

What these are

Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Tornado
A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Hail
Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind
Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Colorado in 1997Every state in 1997This day in weather historyThe tornado archive for Colorado, 1997Warnings in Colorado, June 1997

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5607215, 5608799, 5608801, 5608802, 5608800, 5608804, 5608803, 5608805, 5608806, 5608807, 5608808, 5608809, 5608810, 5608811, 5608812, 5608813, 5607213, 5608814, 5608815, 5607214, 5607212.