Tornadoes · United States · Colorado · 2013
EF1 tornado, Lowry Afb, Colorado, June 18, 2013
This EF1 tornado ran 2.4 miles across Denver County on June 18, 2013, touching down at 2:21 PM MDT and reaching 75 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.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- EF1
- Date
- June 18, 2013
- Touchdown
- 2:21 PM MDT (20:21 UTC)
- Lifted
- 2:36 PM MDT (20:36 UTC)
- On the ground
- 15 minutes
- Path length
- 2.4 miles (3.9 km)
- Path width
- 75 yards (69 m)
- Deaths
- 0
- Injuries
- 0
- County
- Denver County
- Touchdown point
- 39.826, -104.643
- Lift-off point
- 39.858, -104.659
- Record number
- 1306181421-01
What the Weather Service recorded
A landspout tornado touched down at Denver International Airport. The tornado sent 10 thousand travelers on the concourse, on planes and in the terminal scrambling to get into tornado shelters. The tornado formed just to the south of Runway 35R and then moved slowly northwest between Runway 35R and 35L, and moved to within one third of a mile of Concourses A and B before dissipating. The tornado moved extremely close if not over the ASOS (Automated Surface Observation System) and another low level wind shear sensor at DIA. The ASOS weather observing system reported a 97 mph wind gust, while the wind shear sensor reported a wind gust to 109 mph at the same time ��� indicative of an EF1 tornado. There was only minor damage noted to this equipment. Nine flights were diverted elsewhere during a tornado warning. Severe thunderstorms also produced large hail up to quarter size in Adams and Weld Counties.
A tornado touched down east of the Denver International Airport Concourses but caused only minor damage.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
12 minutes of warning. NWS BOU issued a tornado warning for this county at 20:09 UTC, 12 minutes before the tornado touched down, in force until 20:45 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 20:09 UTC | 20:45 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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 20:01 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 (KDNR), 12:00Z
8.4 hours before the tornado, 121 km from the path. June 18, 2013.
- Mixed-layer CAPE
- 448 J/kg
- Mixed-layer CIN
- -285 J/kg
- Surface CAPE
- 301 J/kg
- Mixed-layer LCL
- 1028 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 61 m²/s²
- 0-3 km storm-relative helicity
- 13 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 5.2 K/km
Denver, CO (KDNR), 00:00Z
3.6 hours after it, 121 km from the path. June 19, 2013.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -68685 J/kg
- Surface CAPE
- 307 J/kg
- Mixed-layer LCL
- 3507 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km bulk shear
- 4 kt
- 0-1 km storm-relative helicity
- -13 m²/s²
- 0-3 km storm-relative helicity
- 44 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.2
- 0-3 km lapse rate
- 9.2 K/km
The surface observations
Denver Intnl Airport (DEN), 1 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 | 83 | 45 | 130° 14 kt | 20 | 1017.3 | |
| 19:53 UTC | 82 | 42 | 170° 7 kt | 14 | 1016.3 | TS |
| 20:20 UTC | 69.8 | 44.6 | 70° 20 kt | 28 | 1016.9 | FC +TSRA |
| 20:21 UTC | 69.8 | 42.8 | 60° 22 kt | 28 | 1016.9 | +FC TSRA |
| 20:22 UTC | 69.8 | 44.6 | 60° 21 kt | 28 | 1016.6 | +FC TSRA |
| 20:32 UTC | 71.6 | 46.4 | 90° 26 kt | 1016.3 | +FC -TSRA | |
| 20:37 UTC | 75.2 | 39.2 | 90° 26 kt | 1016.6 | -TSRA | |
| 20:50 UTC | 71.6 | 48.2 | 90° 12 kt | 1016.9 | TS | |
| 20:53 UTC | 71 | 52 | 100° 12 kt | 20 | 1016.6 | TS |
| 21:10 UTC | 75.2 | 48.2 | 90° 16 kt | 1016.3 | ||
| 21:53 UTC | 79 | 43 | 110° 21 kt | 27 | 1015.6 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Denver radar (KFTG), 11 km away, was scanning. The volume nearest the touchdown began at 20:19 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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 20:22 UTC | TORNADO | Denver Intl Airport | Denver, CO | TORNADO TOUCHDOWN EAST OF DIA CONCOURSES. ASOS REPORTED 97 MPH GUST. |
| 21:03 UTC | HAIL 1 | 3 S Keenesburg | Weld, CO | |
| 21:33 UTC | HAIL 1 | 7 Se Bennett | Arapahoe, CO |
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 June 18, 2013
2 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.