EF4 Sibley–Little Rock tornado, Iowa, June 25, 2010

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 mph

   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 mphthis tornado

   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

EF4

Date

June 25, 2010

Touchdown

9:53 PM CDT (02:53 UTC)

Lifted

10:30 PM CDT (03:30 UTC)

On the ground

37 minutes

Path length

13.7 miles (22.0 km)

Path width

800 yards (732 m)

Deaths

0

Injuries

13

Property damage

$3.5 million

Counties

Lyon and Osceola counties

Touchdown point

43.440, -95.951

Lift-off point

43.377, -95.696

Record number

1006252053-01

Thunderstorms produced tornadoes, one that caused considerable damage and at least two injuries along a 14 mile path, along with damaging winds, in northwest Iowa during the evening of June 25th.

A tornado, moving into Osceola County from Lyon County, destroyed at least two houses, injuring two people in one of them. the tornado also destroyed several garages and severely damaged several other homes, destroyed at least 4 hog confinement buildings, several barns and silos, and numerous outbuildings. The tornado destroyed three vehicles that had been parked under an Iowa Highway 60 overpass, injuring 11 people in the vehicles, and removing the engine from one of the vehicles. The tornado damaged power lines, causing power outages, and caused damage to trees and crops. The tornado also destroyed a shelter belt and severely damaged heavy farm equipment, removing the wheels from some of the vehicles. Much of the damage occurred a short distance west to south of the town of Sibley.

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

0 minutes of warning. NWS FSD issued a tornado warning for this county at 02:53 UTC, 0 minutes before the tornado touched down, in force until 03:30 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 01:01 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 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.

Sheldon (SHL), 22 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Sioux Falls radar (KFSD), 76 km away, was scanning. The volume nearest the touchdown began at 02:52 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 2010 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

21 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.