F1 tornado, Clayton to Hartshorne, Oklahoma, May 4, 1999

1. F040 to 72 mph

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

2. F173 to 112 mphthis tornado

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

3. 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.

4. 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.

5. F4207 to 260 mph

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

6. 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.

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.

Rating

F1

Date

May 4, 1999

Touchdown

10:50 AM CDT (15:50 UTC)

Path length

1.0 miles (1.6 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$1,000

Counties

Pushmataha and Pittsburg counties

Touchdown point

34.580, -95.580

Lift-off point

34.570, -95.530

Record number

1087

Summary of events for May 3-4 1999:Following a week-long blocking weather pattern, a strong upper level trough finally moved out of the southwestern U.S. Interactions with a dryline in western Oklahoma and a slow-moving cold front brought the largest tornado outbreak in Oklahoma history from the afternoon of May 3 through the afternoon of May 4. Most notable was the F5 tornado that moved through southern parts of the Oklahoma City metro area. While the loss of life and the heaviest property damage was limited to central Oklahoma, eastern Oklahoma got into the act with a significant number of tornadoes.While there were dozens of individual storms on May 3 and 4, there are two storms in eastern Oklahoma that stand out as outstanding. The first outstanding storm moved northeast along the I-44 corridor on the evening of May 3, causing F3 damage to Stroud in Lincoln County. The storm went on to cause significant F1 damage in Sapulpa and southwestern portions of the city of Tulsa and millions of dollars in damage.The second outstanding storm got its start in southeast Oklahoma well south of McAlester. This storm moved northeast across Pushmataha, Latimer, Haskell, LeFlore and Sequoyah Counties, producing several damaging tornadoes along the way. The final tornado touched down in Sequoyah County and tracked 39 miles to near Fayetteville, AR, producing F3 damage in an unpopulated forest in Adair County.Following a very wet April that saturated area grounds, another slow-moving weather system made flash flooding another serious problem to deal with as most rainfall quickly ran off into creeks, streams and mainstem rivers. One flash flood in Vinita caused millions of dollars in damage following the flooding of dozens of homes.

An F1 tornado touched down briefly near the Pushmataha/Pittsburg County line off of OK Hwy 43 in an unpopulated area 13 miles west of Clayton. After causing some tree damage, the tornado crossed briefly in Pittsburg County before lifting.

An F1 tornado touched down briefly near the Pittsburg/Pushmataha County line along OK Hwy 43. The tornado crossed the county line in an unpopulated area, causing only tree damage.

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

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.

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 Storm Prediction Center had this point in a Moderate Risk. The outlook in force was issued at 12:23 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 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.

The Western Arkansas radar (KSRX), 135 km away, was scanning. The volume nearest the touchdown began at 15:50 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.

The live radar over the trackEvery 1999 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

42 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.