EF1 tornado, Silva to Gravelton, Missouri, April 25, 2011

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 25, 2011

Touchdown

5:47 PM CDT (22:47 UTC)

Lifted

6:00 PM CDT (23:00 UTC)

On the ground

13 minutes

Path length

11.8 miles (19.0 km)

Path width

200 yards (183 m)

Deaths

0

Injuries

0

Property damage

$25,000

County

Wayne County

Touchdown point

37.128, -90.534

Lift-off point

37.152, -90.300

Record number

1104251647-01

A surface low pressure center developed northeastward from south central Oklahoma to southwest Missouri. A gradual increase in the warm sector southerly low level jet occurred as the surface low deepened. Increasing vertical wind shear in the moist and unstable warm sector supported the development of short lines of thunderstorms with embedded lewps and supercell structures.

Structural damage was limited to the side of a church. The tornado uprooted and snapped dozens of oaks and pines. The heaviest damage was in a forested area, where peak winds were estimated near 100 mph.

At a horse ranch near Clubb, the tornado lifted wall panels from a horse arena, lifted a segment of roofing from a house, uprooted trees, and heavily damaged a 111-year-old barn. Numerous power poles were snapped. The trees exhibited a convergent pattern, and tin from the arena was circulated, including some that was found 200 yards south of the arena. The tornado continued on the ground uprooting trees, maximizing intensity as it crossed County Road 216. The remainder of the path was through forested areas, including a conservation area. Peak winds were estimated near 105 mph.

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

9 minutes of warning. NWS PAH issued a tornado warning for this county at 22:38 UTC, 9 minutes before the tornado touched down, in force until 23:15 UTC.

The county was under a tornado watch, issued at 21:52 UTC and running to 01:44 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:48 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.

Popular Bluff (POF), 42 km from the path, in the two hours either side.

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

The Paducah radar (KPAH), 146 km away, was scanning. The volume nearest the touchdown began at 22:47 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 2011 tornado in MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are

45 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.