Tornadoes · United States · Colorado · 2001
F0 tornado, Bennett, Colorado, July 26, 2001
This F0 tornado ran 0.1 miles across Adams County on July 26, 2001, touching down at 2:15 PM MDT and reaching 50 yards wide. It killed nobody.
The rating scale
Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
F040 to 72 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
F2113 to 157 mph
Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.
F3158 to 206 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
F5261 to 318 mph
Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.
Unrated
The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.
The record
- Rating
- F0
- Date
- July 26, 2001
- Touchdown
- 2:15 PM MDT (20:15 UTC)
- Path length
- 0.1 miles (0.2 km)
- Path width
- 50 yards (46 m)
- Deaths
- 0
- Injuries
- 0
- County
- Adams County
- Touchdown point
- 39.750, -104.020
- Lift-off point
- 39.750, -104.020
- Record number
- 418
What the Weather Service recorded
A small tornado touched down but did no damage.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 20:37 UTC | 21:00 UTC | Tornado Warning | BOU |
Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.
The forecast that day
The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 20:04 UTC.
SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.
What forecasters said that day
The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Denver/Boulder, CO wrote its last area forecast discussion before the tornado touched down at Jul 26, 3:30 AM MDT, 10 hours 45 minutes earlier.
Area forecast discussion, Jul 26, 3:30 AM MDT, 10 hours 45 minutes before
NORTHEAST AND NORTH CENTRAL COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER COLORADO 330 AM MDT THU JUL 26 2001 SHORT TERM: STAGE IS SETTING UP FOR AN ACTIVE WEATHER DAY FOR CWA LATER THIS AFTN AND TONIGHT. MOISTURE PLUME FROM MEXICO CONTINUES STREAMING INTO CO WITH PW VALUES AROUND AN INCH. MAIN PLAYER FOR OUR WEATHER WILL BE WEAKENING LOW NOW LIFTING TO THE NORTHEAST ACROSS NW ARIZONA. THIS TROUGH WILL BE MOVE ACROSS NW CO LATER THIS AFTN AND WEAKEN AND SHIFT THRU CWA DURING THE NIGHT. DIV-Q FIELDS SHOWING FAIRLY DECENT UPWARD FORCING ESPECIALLY FOR THE SUMMER TIME. FORCING IS ALSO AIDED BY 60KT SPEED MAX AS TROF LIFTS ACROSS REGION. AT THE SURFACE...WEAK SURGE HAS BACKED INTO FAR NERN CO FROM OVERNIGHT COMPLEX IN NEBRASKA WITH INCREASING LOW LEVEL MOISTURE(SFC DEWPOINTS IN MID 60S) ON E-SE WINDS. SAT PICS ALSO SHOW STRATUS/FOG MOVING IN AS WELL. DON'T THINK IT WILL MAKE IT ALL THE WAY BACK TO DEN...BUT WILL ADD SOME FOG FOR ERN PLAINS ZONES THIS MORNING. WITH THE INCREASING S-SE FLOW...EXPECT A DENVER CYCLONE OR CONVERGENCE LINE TO SET UP OVER OR JUST EAST OF THE URBAN COORIDOR DURING THE AFTERNOON. THIS SHOULD BE THE FOCUS FOR A SEVERE WX SET UP LATER THIS AFTN/EVENING. 06Z MESOETA SHOWING CAPES AROUND 2000-2500J/KG EAST OF DENVER OVER THE PLAINS...AND BETWEEN 1000-1500 J/KG FOR WESTERN PTNS OF CWA. THE DIFFERENCE TODAY IN COMPARISON TO LAST FEW DAYS IS THE HIGHER CAPES...GREATER LOW LVL MSTR AND STRONGER MID LVL FLOW. ALSO STORM REL HELICITIES ALSO LOOKING GOOD WITH VALUES BETWEEN 200-300M2/S2. EXPECT STRONGEST STORMS CAN PRODUCE LARGE HAIL UP TO 2 INCHES IN DIAMETER AND EVEN AN ISOLATED TORNADO NOT OUT OF THE QUESTION WITH THIS NICE DIRECTIONAL SHEAR PROFILE SETTING UP. WILL MENTION POSSILBE SEVERE STORMS IN ZONES FOR TNT OVER THE PLAINS. TIMING OF STORMS SHOULD BE ON THE LATE SIDE AGAIN TODAY...WITH MTNS/HIR TERRAIN GOING FIRST AGAIN BY MID AFTERNOON...URBAN COORIDOR AND ADJ EAST SECTIONS BTWN 22-00Z...AND EASTERN PLAINS THIS EVENING. THE LATE FIRING DUE TO MORE CLOUD COVER/FOG EASTERN PTNS THIS MORNING...AND UPR SUPPORT NOT REALLY IN HERE UNTIL AFT 00Z. LONG TERM: WEATHER WILL BE CALMING DOWN ON FRIDAY...BUT PIECE OF TROF LAGGING BEHIND FRI AFTN AND MAY CREATE SOME THUNDERSTORMS OVER THE FAR EAST PLAINS. WESTERN PTNS OF CWA SHOULD BE DRYING OUT WITH SUBSIDENCE MOVING IN WITH ISOLD TS COVERAGE AT BEST. WEEKEND STILL LOOKING RATHER DRY WITH STRONGER WESTERLY FLOW...BUT CAN'T RULE OUT AN ISOLD TSRA. UPPER HIGH SHIFTS EAST AGAIN NEXT WEEK AND TS CHANCES SHOULD INC. THIS COVERED WELL IN ZONES. ENTREKIN .DEN...NONE.
In the hours before
Special weather statement, Jul 26, 10:30 AM MDT, 3 hours 45 minutes before
COZ030>051-262000- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 1030 AM MDT THU JUL 26 2001 THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD SYNOPSIS: AN UPPER LEVEL TROUGH...LOCATED OVER NORTHWESTERN ARIZONA WILL SLOWLY MAKE ITS WAY ACROSS WESTERN AND NORTHERN COLORADO LATE THIS AFTERNOON AND TONIGHT. IN ADDITION...SOUTHEASTERLY SURFACE WINDS ARE EXPECTED TO INCREASE AHEAD OF THIS SYSTEM...ALLOWING THE LOW LEVEL MOISTURE TO REMAIN IN PLACE ACROSS THE NORTHEASTERN PLAINS AND URBAN CORRIDOR. SUFFICIENT SHEAR WILL BE PRESENT FOR THE DEVELOPMENT OF LARGE HAIL ...DAMAGING WINDS AND POSSIBLY AN ISOLATED TORNADO. HEAVY RAINFALL ...UP TO 2 INCHES PER HOUR...AND FREQUENT CLOUD TO GROUND LIGHTNING WILL ALSO OCCUR WITH THE STORMS. THE GREATEST POTENTIAL FOR SEVERE THUNDERSTORMS APPEARS TO BE EAST OF INTERSTATE 25. THE MAIN LIMITATION MAY BE THE EXTENSIVE CLOUD COVER PRESENTLY OVER NORTHEASTERN COLORADO. THIS MAY DELAY THE ONSET OF THE STRONGER THUNDERSTORMS UNTIL LATE THIS AFTERNOON. SCATTERED THUNDERSTORMS WILL DEVELOP IN THE MOUNTAINS AND FOOTHILLS AFTER 1200 PM...MOVING INTO THE URBAN CORRIDOR AFTER 3 PM. SPOTTER ACTIVATION MAY BE NEEDED AT THAT TIME. COOPER
Special weather statement, Jul 26, 1:15 PM MDT, 1 hour before
COZ030>051-262100- SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO NATIONAL WEATHER SERVICE DENVER CO 115 PM MDT THU JUL 26 2001 THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES ADAMS ARAPAHOE BOULDER CLEAR CREEK DENVER DOUGLAS ELBERT GILPIN GRAND JACKSON JEFFERSON LARIMER LINCOLN LOGAN MORGAN PARK PHILLIPS SEDGWICK SUMMIT WASHINGTON WELD SYNOPSIS: A WEAK UPPER LEVEL DISTURBANCE WILL EXIT NORTHERN COLORADO EARLY THIS AFTERNOON...WITH THE MAIN UPPER LEVEL TROUGH EXPECTED TO SLOWLY MAKE ITS WAY ACROSS WESTERN AND NORTHERN COLORADO TONIGHT. ENOUGH VERTICAL WIND SHEAR MAY BE PRESENT THROUGH EARLY THIS EVENING FOR THE DEVELOPMENT OF A FEW SEVERE THUNDERSTORMS. THESE STORMS COULD PRODUCE LARGE HAIL...DAMAGING WINDS AND EVEN AN ISOLATED TORNADO. HEAVY RAINFALL...UP TO 2 INCHES IN LESS THAN AN HOUR...AND FREQUENT CLOUD TO GROUND LIGHTNING WILL ALSO OCCUR. SHOULD THE STORMS REMAIN STATIONARY OR TRAIN OVER THE SAME LOCATION...THEN POTENTIAL FLOODING OR FLASH FLOODING PROBLEMS MAY ALSO DEVELOP. AT 1 PM MDT...SATELLITE DATA INDICATED DRIER AIR IN THE MID LEVELS WAS MOVING IN FROM THE SOUTH. IF AFTERNOON TEMPERATURES CAN WARM INTO THE MID 80S...THEN THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS WILL INCREASE SIGNIFICANTLY. THE GREATEST POTENTIAL FOR SEVERE WEATHER APPEARS TO BE ALONG AND EAST OF A BOUNDARY THAT EXTENDED FROM NEW RAYMER TO BYERS TO CASTLE ROCK. SPOTTER ACTIVATION MAY BE NEEDED AFTER 3 PM. COOPER
The air that afternoon
The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.
Denver, CO (KDNR), 12:00Z
8.3 hours before the tornado, 69 km from the path. July 26, 2001.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -72311 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 1935 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km bulk shear
- 8 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 46 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 4.8 K/km
Denver, CO (KDNR), 00:00Z
3.7 hours after it, 69 km from the path. July 27, 2001.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -76280 J/kg
- Surface CAPE
- 264 J/kg
- Mixed-layer LCL
- 2110 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- -46 m²/s²
- 0-3 km storm-relative helicity
- 4 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
- 0-3 km lapse rate
- 8.1 K/km
The surface observations
Denver Intnl Airport (DEN), 55 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 18:53 UTC | 78 | 58 | 320° 11 kt | 1019.3 | ||
| 19:53 UTC | 75 | 55 | 310° 17 kt | 23 | 1019.6 | |
| 20:53 UTC | 76 | 53 | 320° 20 kt | 25 | 1018.6 | |
| 21:53 UTC | 77 | 54 | 330° 12 kt | 1019 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Denver radar (KFTG), 45 km away, was scanning. The volume nearest the touchdown began at 20:15 UTC.
Open the radar archive at this moment, over the track
Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.
This ground now
The live radar over the trackEvery 2001 tornado in ColoradoEvery tornado in Colorado since 1950Warnings in force in Colorado nowThe forecast where you are
The other tornadoes of July 26, 2001
5 more were confirmed in the United States that day.
What this means
Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.