EF1 tornado, El Reno to Piedmont, Oklahoma, May 8, 2007

1. EF065 to 85 mph

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

2. EF186 to 110 mphthis tornado

   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.

Rating

EF1

Date

May 8, 2007

Touchdown

12:08 AM CDT (05:08 UTC)

Path length

0.6 miles (1.0 km)

Path width

80 yards (73 m)

Deaths

0

Injuries

0

County

Canadian County

Touchdown point

35.622, -97.832

Lift-off point

35.622, -97.832

Record number

0705082308-01

An upper level storm system moved slowly east northeast through southeast Arizona and southwest New Mexico. A couple of disturbances rotated around the storm system and moved over the southern plains during the morning and afternoon hours. One disturbance moved over Oklahoma during the morning hours, with the other moving over Oklahoma during the evening hours. A stationary front remained located south of the Red River, with another front establishing itself over the southeast third of Oklahoma. Showers and thunderstorms developed and moved over the main body of Oklahoma during the morning hours. Widespread flash flooding was reported over central Oklahoma, with rivers rising out of their banks. After a lull in precipitation for a few hours the other disturbance moved over Oklahoma during the late afternoon and evening hours. Widespread showers and thunderstorms developed over southwest Oklahoma and continued to develop into central and southern Oklahoma. Large hail and severe wind gusts were reported, with flash flooding and river flooding continuing to be a concern due to the heavy rainfall earlier in the day. Supercell thunderstorms formed in southwest Oklahoma producing one tornado near Lake Ellsworth. As the showers and storms continued to develop and move northeast, a mesoscale convective vorticity maximum (MCV) developed. In the vicinity of this MCV, transient circulations on many scales were observed in the storm-relative radar velocity fields and in the storm motions themselves. Some of the circulations briefly tightened to tornado scale causing damage west of Minco, west of Union City, and in El Reno. Monetary damages were estimated.

A tornado developed and moved north through parts of El Reno. The first damage occurred in a complex of industrial/commercial buildings is located on the southwest corner of I-40 and Hwy 81. One building suffered minor roof damage with the roofing peeled away. Another metal building had partial peeling of the side paneling, a large garage door blown in and the business���s dumpster was rolled 100 ft to the west. An outbuilding supply business had its several garage doors blown in and a display outbuilding collapsed and was moved. Some trees in the area were damaged and the damage varied over a wide range. Trees closer to the interstate had large branches and trunks snapped, while trees closer to Hwy 81 were either tipped or limbs up to 6��� were snapped. Farther to the west, a building that was under construction had some building material blown to the north northeast towards the area of apparent touchdown. Two businesses just south southwest of the touchdown point also had damage to their garage doors.||Directly across I-40 from the touchdown point was a car dealership. The main building at the dealership had minimal damage and most vehicles in the lot had no damage. One light pole was knocked over and a large sign for the dealership was damaged. A double wide mobile home, which was used as an office at the dealership, was knocked over on its side. Several cars towards the extreme northwest corner of the lot exhibited damage though the original locations of the vehicles are in question. Billboards around the lot were either destroyed or folded over. Farther to the northwest a farm house with outbuildings sustained damage. Most damage appeared to be suffered by the outbuildings. The damage appeared minor with roof and side panels peeled, though one of the buildings sustained some damage to its structure. The tornado then entered into an industrial area. A building west of the farm house sustained damage to its office area and a section of side paneling was peeled. Roofing from the Oklahoma Gas and Electric building, which was across the street, also impacted the northeast corner of the building with enough force to cause a significant dent in the panel. A flag pole at this building was also bent about 50 degrees. The building seemed to have sustained the most damage in the area. It appeared most of the roof was gone, a tree was snapped in two and the power lines were snapped in two. Further, the roof of the small office area appeared to have been partially lifted. A pole near the building also appears to have bent a bit. Other buildings near the building had other damage to siding and roofs.||Along Hwy 81, north of Oklahoma Gas and Electric, several buildings in the industrial/commercial area sustained damage. A convenience store had its windows blown out, a garage door blown out, and a portion of the roof was removed. Metal framed buildings to the west of this area failed at the ends of the buildings but the center portions of the framing remained intact. One structure in particular lost most of its roof and it is believed that this roof actually scraped along and removed the roof to a small strip mall. A metal building to the north of this strip mall had a garage door blown in and two panels were pushed in towards the bottom of the panel on its south side. On the north side the building had 3 garage doors blown in and the northeast corner sustained side panel damage. Across Hwy 81, a snow cone hut was spun about 270 degrees and a metal lining peeled off. Two metal light poles near the hut were damaged; one was bent and another was snapped off its base. To the north of this area a building sustained damage to its roof. People were present inside the building when it was struck but no one was injured. Three power poles, one towards the highway and two near the building were snapped. A storage shed on the north side of the building's parking lot had a garage door blown in; also, plastic skylights were blown out to locations unknown. Power poles just to the north along a side road were blown over and one was snapped. West of this location was a farm supply store which had grain bins blown over and some into a nearby pond. North of the store was a cluster of trees which had a variety of damage. The final damage points were along Choctaw Rd. At the corner of Choctaw and Elm, a metal building had its roof rotated on top it and a power pole near it was snapped. The neighborhood west of Choctaw Rd had some tree and power pole damage. Also the neighborhood northeast of Hwy 81 and Elm sustained probable microburst damage. Monetary damages were estimated.

A short narrow damage path from a tornado was observed between Gregory Road and Cimarron Road, and just south of Northwest Expressway. A few trees were downed, a tin shed was destroyed, and two roofs were damaged.

A brief tornado caused mainly minor damage north northwest of Piedmont. Most of the damage was confined to an area along and near Duboise Road. A car was pushed into another car, denting the fender. Homes suffered shingle damage. One brick home was shifted on its foundation. Another car was rotated 90 degrees by the wind. Monetary damages were estimated.

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

20 minutes of warning. NWS OUN issued a tornado warning for this county at 04:48 UTC, 20 minutes before the tornado touched down, in force until 05:15 UTC.

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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 00:35 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 Norman radar (KTLX), 60 km away, was scanning. The volume nearest the touchdown began at 05:06 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.

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

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

The live radar over the trackEvery 2007 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

8 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.