EF1 tornado, Kelso to Bernice, Oklahoma, April 2, 2015

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

April 2, 2015

Touchdown

9:59 PM CDT (02:59 UTC)

Lifted

10:19 PM CDT (03:19 UTC)

On the ground

20 minutes

Path length

12.3 miles (19.8 km)

Path width

800 yards (732 m)

Deaths

0

Injuries

1

Property damage

$275,000

Counties

Craig, Ottawa and Delaware counties

Touchdown point

36.705, -95.095

Lift-off point

36.656, -94.885

Record number

1504022059-01

49 damage points were recorded along this path by NWS TSA, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 107 mph.

• numerous trees snapped or uprooted; clearly convergent pattern this area
• boat dock turned upside down
• tornado crossed hill on other side of lake; numerous trees uprooted or snapped
• snapped trees this area also

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

Severe thunderstorms developed during the evening of the 2nd near a stationary frontal boundary that extended across northeastern Oklahoma and southeastern Kansas. A very unstable air mass over the region coupled with strong vertical wind shear resulted in some supercell thunderstorm structures. The storms produced hail up to golfball size, wind gusts of up to 80 mph, and a damaging tornado.||A complex of storms that formed in eastern Colorado and western Kansas translated southeastward during the evening and across portions of far northeastern Oklahoma during the early morning hours of the 3rd. Damaging wind occurred in northern Craig County, from the southernmost storm in that complex.

This is the first segment of a three segment tornado. In Craig County, the tornado first damaged barns and trees at the S 440 Road. It moved east-southeast snapping or uprooting trees and damaging barns and outbuildings along the E 200 Road, the S 440 Road, and the E 230 Road before crossing I-44, where it blew over two tractor trailers, injuring the driver of one of them. Based on this damage, maximum estimated wind in this segment of the tornado was 95 to 105 mph. The tornado continued into Ottawa County, Oklahoma.

This is the second segment of a three segment tornado. In Ottawa County, the tornado moved through open country and then crossed Highway 60 where it threw several round hay bales. It destroyed barns and outbuildings, damaged several homes, and snapped or uprooted numerous trees as it crossed the S 510 Road and S 520 Road. Based on this damage, maximum estimated wind in this segment of the tornado was 95 to 105 mph. The tornado continued into Delaware County, Oklahoma.

This is the third of three segments of this tornado. The tornado crossed into Delaware County near the S 520 Road. Trees were snapped or uprooted, barns and outbuildings were damaged, and homes were damaged as it approached the north end of Grand Lake from the west-northwest. It destroyed a private boat dock on the lake then moved through a community of houses to the east of the lake, resulting in damage to the roofs of homes as well as tree damage. The tornado dissipated to the east of this community in open country. Based on this damage, estimated maximum wind in this segment of the tornado was 95 to 105 mph.

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.

The county was under a tornado watch, issued at 00:05 UTC and running to 04:44 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 Enhanced Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 00:49 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 Tulsa radar (KINX), 76 km away, was scanning. The volume nearest the touchdown began at 02:59 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 2015 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

12 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.