Tornadoes · United States · Colorado · 2013

EF0 tornado, Ft Morgan, Colorado, August 3, 2013

This EF0 tornado ran 0.1 miles across Morgan County on August 3, 2013, touching down at 2:00 PM MDT and reaching 50 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 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.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 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.

  7. 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
EF0
Date
August 3, 2013
Touchdown
2:00 PM MDT (20:00 UTC)
Lifted
2:03 PM MDT (20:03 UTC)
On the ground
3 minutes
Path length
0.1 miles (0.2 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Morgan County
Touchdown point
40.270, -103.790
Lift-off point
40.270, -103.790
Record number
1308031400-01

What the Weather Service recorded

Severe thunderstorms brought damaging hail, wind, tornadoes, heavy rain and flash flooding to portions of the Urban Corridor and Northeast Plains. Very large hail, ranging from quarter to softball size, caused extensive damage to property and crops. Several small and brief non supercell tornadoes touched down but did little if any damage. Most the damage was the result of the large hail, intense thunderstorm winds, heavy rain and flash flooding. In Erie, a velodrome under construction was heavily damaged.

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

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

7 minutes of warning. NWS BOU issued a tornado warning for this county at 19:53 UTC, 7 minutes before the tornado touched down, in force until 20:30 UTC.

Issued (UTC)ExpiredProductOffice
19:35 UTC20:15 UTCSevere Thunderstorm WarningBOU
19:53 UTC20:30 UTCTornado WarningBOU
20:11 UTC20:45 UTCTornado WarningBOU
20:15 UTC23:15 UTCFlash Flood WarningBOU
20:28 UTC21:00 UTCTornado WarningBOU
20:35 UTC01:07 UTCTornado WatchBOU
20:41 UTC21:15 UTCTornado WarningBOU
21:16 UTC21:24 UTCTornado WarningBOU
23:45 UTC00:16 UTCTornado WarningBOU

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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:45 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.

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 (KDEN), 12:00Z

8.0 hours before the tornado, 65 km from the path. August 3, 2013.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2013-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 46 joules per kilogram, CIN -295, lifted condensation level 2189 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Denver, CO at 12:00Z on 2013-08-03The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 32 square meters per square second, 0 to 6 km bulk shear 15 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
46 J/kg
Mixed-layer CIN
-295 J/kg
Surface CAPE
5 J/kg
Mixed-layer LCL
2189 m above ground
0-6 km bulk shear
15 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

Denver, CO (KDEN), 00:00Z

4.0 hours after it, 65 km from the path. August 4, 2013.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 00:00Z on 2013-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 233 joules per kilogram, CIN -148, lifted condensation level 1656 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Denver, CO at 00:00Z on 2013-08-04The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 225 square meters per square second, 0 to 6 km bulk shear 38 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
233 J/kg
Mixed-layer CIN
-148 J/kg
Surface CAPE
857 J/kg
Mixed-layer LCL
1656 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
20 kt
0-1 km storm-relative helicity
225 m²/s²
0-3 km storm-relative helicity
290 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
7.1 K/km

Open this sounding in Storm Lab

The surface observations

Fort Morgan (FMM), 7 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
18:15 UTC130° 8 kt1020
18:35 UTC120° 10 kt191020
18:55 UTC80° 19 kt231020
19:15 UTC60° 24 kt371019.6
19:35 UTC30° 13 kt231021TS
19:55 UTC6865.6650° 20 kt311021.3TS
20:15 UTC6765.3100° 23 kt311021.7TS
20:35 UTC66.264.58100° 24 kt351021.7TS
20:55 UTC66.264.76100° 25 kt331021TS
21:15 UTC6764.76120° 20 kt261021
21:35 UTC67.8261.16120° 17 kt281021
21:55 UTC6964.4120° 19 kt301021VCTS

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Denver radar (KFTG), 84 km away, was scanning. The volume nearest the touchdown began at 20:01 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
20:02 UTCTORNADO2 S Fort MorganMorgan, COBRIEF TORNADO IN OPEN FIELD. ON GROUND FOR 1-2MIN WITH NO DAMAGE REPORTED.
20:03 UTCTORNADO3 N Fort MorganMorgan, COSHORT LIVED TORNADO IN OPEN FIELD WITH NO REPORTS OF DAMAGE.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2013 tornado in ColoradoEvery tornado in Colorado since 1950Warnings in force in Colorado nowThe forecast where you are

The other tornadoes of August 3, 2013

7 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 33:37 PM MDTEF0Washington, CO0.150
August 34:07 PM MDTEF0Lincoln, CO0.150
August 34:17 PM MDTEF0Weld, CO0.150$5,000
August 34:29 PM MDTEF0Weld, CO0.150
August 35:24 PM MDTEF0Weld, CO0.150
August 35:40 PM MDTEF0Weld, CO0.150
August 37:15 PM MDTEF0Powder River, MT1.0100

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.