Tornadoes · United States · Oklahoma · 2018
EF1 tornado, Chickasha Arpt to Amber, Oklahoma, May 2, 2018
From Chickasha Arpt to Amber, this EF1 tornado ran 0.4 miles across Grady County on May 2, 2018, touching down at 8:05 PM CDT and reaching 25 yards wide. It killed nobody, and did $10,000 of property damage.
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
- May 2, 2018
- Touchdown
- 8:05 PM CDT (01:05 UTC)
- Lifted
- 8:06 PM CDT (01:06 UTC)
- On the ground
- 1 minutes
- Path length
- 0.4 miles (0.6 km)
- Path width
- 25 yards (23 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $10,000
- County
- Grady County
- Touchdown point
- 35.160, -97.866
- Lift-off point
- 35.165, -97.863
- Record number
- 1805021905-01
What the Weather Service recorded
Several discrete supercells formed off a dryline in the eastern parts of the panhandles in the late afternoon of the 2nd. These storms moved eastward through the evening, eventually congealing into a line before coming across central Oklahoma. QLCS tornadoes became a significant hazard at this point. After this round of storms made its way out of the area, scattered storms began to form from central Texas up into south western Oklahoma overnight, moving generally northeast into the early morning hours.
This tornado developed approximately 4 miles west-southwest of Amber, briefly moved northeast before turning east-southeast. A barn and an RV were damaged southwest of Amber, and power poles were damaged south of Amber. Tree damage was also noted just west of Interstate 44, but the tornado did not appear to cross I-44.
As one tornado was dissipating south-southeast of Amber, this tornado developed approximately 1 mile east of Amber. Trees were snapped, a roof was damaged and a carport destroyed from this brief tornado as it moved northeast.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
3 minutes of warning. NWS OUN issued a tornado warning for this county at 01:02 UTC, 3 minutes before the tornado touched down, in force until 01:31 UTC.
The county was under a tornado watch, issued at 18:01 UTC and running to 03:00 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 18:01 UTC | 03:00 UTC | Tornado Watch | OUN |
| 22:57 UTC | 23:45 UTC | Severe Thunderstorm Warning | OUN |
| 23:36 UTC | 00:15 UTC | Severe Thunderstorm Warning | OUN |
| 23:43 UTC | 00:30 UTC | Severe Thunderstorm Warning | OUN |
| 00:11 UTC | 01:00 UTC | Severe Thunderstorm Warning | OUN |
| 00:30 UTC | 01:30 UTC | Severe Thunderstorm Warning | OUN |
| 00:43 UTC | 03:45 UTC | Flood Advisory | OUN |
| 00:44 UTC | 01:30 UTC | Severe Thunderstorm Warning | OUN |
| 01:00 UTC | 01:30 UTC | Severe Thunderstorm Warning | OUN |
| 01:02 UTC | 01:31 UTC | Tornado Warning | OUN |
| 01:04 UTC | 04:00 UTC | Flash Flood Warning | OUN |
| 01:06 UTC | 01:30 UTC | Tornado Warning | OUN |
| 01:17 UTC | 02:00 UTC | Severe Thunderstorm Warning | OUN |
| 01:22 UTC | 04:15 UTC | Flood Advisory | OUN |
| 01:53 UTC | 03:07 UTC | Flash Flood Warning | OUN |
| 05:17 UTC | 06:00 UTC | Severe Thunderstorm Warning | OUN |
| 05:59 UTC | 06:45 UTC | Severe Thunderstorm Warning | OUN |
| 06:53 UTC | 07:19 UTC | Severe Thunderstorm Warning | OUN |
| 06:56 UTC | 07:45 UTC | Severe Thunderstorm Warning | OUN |
| 08:39 UTC | 11:45 UTC | Flood Advisory | OUN |
| 11:20 UTC | 11:45 UTC | Severe Thunderstorm Warning | OUN |
| 11:42 UTC | 12:15 UTC | Severe Thunderstorm Warning | OUN |
| 12:08 UTC | 12:29 UTC | Severe Thunderstorm Warning | OUN |
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 Enhanced Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:52 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.
Norman, OK (KOUN), 00:00Z
1.1 hours before the tornado, 43 km from the path. May 3, 2018.
- Mixed-layer CAPE
- 826 J/kg
- Mixed-layer CIN
- -62 J/kg
- Surface CAPE
- 1222 J/kg
- Mixed-layer LCL
- 930 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 207 m²/s²
- 0-3 km storm-relative helicity
- 231 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 5.3
- 0-3 km lapse rate
- 5.6 K/km
Norman, OK (KOUN), 12:00Z
10.9 hours after it, 43 km from the path. May 3, 2018.
- Mixed-layer CAPE
- 236 J/kg
- Mixed-layer CIN
- -135 J/kg
- Surface CAPE
- 244 J/kg
- Mixed-layer LCL
- 974 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 85 m²/s²
- 0-3 km storm-relative helicity
- 244 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
- 0-3 km lapse rate
- 5.4 K/km
The surface observations
Chickasha Municipal Airport (CHK), 12 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 23:10 UTC | 79.2 | 69 | 140° 15 kt | 18 | 1007.1 | VCTS |
| 23:35 UTC | 78.4 | 69.3 | 140° 12 kt | 1007.5 | TS | |
| 23:50 UTC | 78.4 | 69.4 | 130° 14 kt | 1007.8 | TSHZ | |
| 00:10 UTC | 78 | 69.8 | 130° 17 kt | 21 | 1007.8 | TS |
| 00:30 UTC | 77.7 | 70 | 130° 19 kt | 23 | 1007.5 | TSHZ |
| 00:50 UTC | 71 | 65.3 | 220° 33 kt | 41 | 1010.2 | -TSRA |
| 01:15 UTC | 62.8 | 61.3 | 160° 7 kt | 1011.9 | +TSRA BR | |
| 01:30 UTC | 62.8 | 62 | 100° 20 kt | 24 | 1010.2 | +TSRA BR |
| 01:55 UTC | 64 | 62 | 140° 19 kt | 25 | 1009.8 | TS |
| 02:10 UTC | 64.2 | 62 | 110° 16 kt | 22 | 1009.8 | |
| 02:30 UTC | 64 | 62 | 120° 16 kt | 1010.2 | ||
| 02:50 UTC | 64 | 62.4 | 110° 14 kt | 1009.8 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Norman radar (KTLX), 57 km away, was scanning. The volume nearest the touchdown began at 01:06 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 |
|---|---|---|---|---|
| 23:41 UTC | HAIL 1.25 | Gracemont | Caddo, OK | |
| 23:42 UTC | TSTM WND DMG | 3 Wnw Anadarko | Caddo, OK | METAL ROOF TAKEN OFF HOUSE. |
| 23:51 UTC | HAIL 0.88 | 5 E Binger | Caddo, OK | |
| 00:20 UTC | HAIL 1.5 | 5 Ene Lake Chickasha | Grady, OK | MPING. |
| 01:00 UTC | TSTM WND GST 72 | 4 Wnw Rush Springs | Grady, OK | |
| 01:00 UTC | TORNADO | 5 S Pocasset | Grady, OK | LOFTED DEBRIS VISIBLE. PERHAPS CORRUGATED ROOFING. TORNADO STARTED AT OR JUST EAST OF HWY 81, MOVING NE. PRESENT FOR 2-3 MINS. |
| 01:11 UTC | HAIL 0.75 | 4 Ene Mustang | Oklahoma, OK | |
| 01:35 UTC | FLASH FLOOD | 3 Sw Minco | Grady, OK | LOCAL OFFICIAL REPORTED WATER FLOWING OVER ROADWAYS WEST AND SOUTHWEST OF MINCO. TIME ESTIMATED. |
| 01:44 UTC | TORNADO | 5 Ne Norman | Cleveland, OK | A WEAK TORNADO IMPACTED THE NORTHEASTERN PORTIONS OF NORMAN. EF1 DAMAGE WAS SURVEYED, INCLUDING STRUCTURAL AND HARDWOOD TREE DAMAGE. PRELIMINARY PATH LENGTH IS APPROXIMATELY 8 MILES. |
| 02:03 UTC | FLASH FLOOD | Bethany | Oklahoma, OK | ROUTE 66 IN BETHANY CLOSED DUE TO FLOODING. |
| 02:05 UTC | FLASH FLOOD | 4 Ssw Bethany | Canadian, OK | CAR SUBMERGED IN WATER NEAR RENO AND ALIANCE BLVD/I40 AND COUNCIL. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2018 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are
The other tornadoes of May 2, 2018
29 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 2 | 4:05 PM CDT | EF0 | Ottawa, KS | 0.0 | 20 | |||
| May 2 | 4:25 PM CDT | EF0 | Greer, OK | 1.7 | 30 | |||
| May 2 | 4:38 PM CDT | Unrated | Kiowa, OK | 1.2 | 30 | |||
| May 2 | 4:51 PM CDT | EF0 | McPherson, KS | 2.0 | 75 | |||
| May 2 | 5:30 PM CDT | EF0 | Marshall, KS | 2.3 | 30 | |||
| May 2 | 5:46 PM CDT | Unrated | Wilbarger, TX | 0.2 | 25 | |||
| May 2 | 5:47 PM CDT | EF0 | Marshall, KS | 7.7 | 60 | |||
| May 2 | 6:10 PM CDT | Unrated | Tillman, OK | 0.5 | 20 | |||
| May 2 | 6:21 PM CDT | Unrated | Tillman, OK | 0.4 | 20 | |||
| May 2 | 6:26 PM CDT | EF1 | Tillman, OK | 1.6 | 50 | $5,000 | ||
| May 2 | 6:34 PM CDT | EF1 | Tillman, OK | 5.5 | 150 | $5,000 | ||
| May 2 | 6:47 PM CDT | EF2 | Tillman, OK | 4.1 | 600 | $5,000 | ||
| May 2 | 6:51 PM CDT | EF0 | Butler, KS | 0.8 | 75 | |||
| May 2 | 7:02 PM CDT | Unrated | Tillman, OK | 3.5 | 50 | |||
| May 2 | 7:07 PM CDT | EF1 | Tillman, OK | 3.0 | 250 | $4,000 | ||
| May 2 | 7:18 PM CDT | EF0 | Holt, MO | 4.0 | 25 | |||
| May 2 | 7:45 PM CDT | EF0 | Lyon, KS | 0.0 | 20 | |||
| May 2 | 7:51 PM CDT | EF0 | Coffey, KS | 0.0 | 25 | |||
| May 2 | 7:55 PM CDT | EF1 | Grady, OK | 10.0 | 400 | $30,000 | ||
| May 2 | 7:58 PM CDT | EF1 | Grady, OK | 5.5 | 100 | $20,000 | ||
| May 2 | 8:04 PM CDT | EF0 | Osage, KS | 0.0 | 25 | |||
| May 2 | 8:42 PM CDT | EF1 | Cleveland, OK | 8.0 | 400 | $10,000 | ||
| May 2 | 8:48 PM CDT | EF1 | McClain, OK | 4.7 | 40 | $10,000 | ||
| May 2 | 9:09 PM CDT | EF1 | Johnson, KS | 4.7 | 25 | |||
| May 2 | 9:19 PM CDT | EF1 | Pottawatomie, OK | 0.8 | 50 | $2,000 | ||
| May 2 | 9:22 PM CDT | EF0 | Cass, MO | 0.0 | 10 | |||
| May 2 | 9:24 PM CDT | EF0 | Jackson, MO | 1.6 | 25 | |||
| May 2 | 9:26 PM CDT | EF0 | Jackson, MO | 1.3 | 25 | |||
| May 2 | 10:39 PM CDT | EF0 | Crockett, TX | 0.8 | 50 | $50,000 |
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.