EF1 tornado, Williamsburg, Missouri, May 19, 2017

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 19, 2017

Touchdown

4:15 AM CDT (09:15 UTC)

Lifted

4:16 AM CDT (09:16 UTC)

On the ground

1 minutes

Path length

1.6 miles (2.5 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

County

Callaway County

Touchdown point

38.917, -91.683

Lift-off point

38.918, -91.654

Record number

1705190315-01

13 damage points were recorded along this path by NWS LSX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 100 mph.

• Damage to hanger building with roof panels removed and window/door blown out.
• Barn destroyed with debris thrown east into adjoining field.
• Broken power pole at this location.
• Tornado ended here. Few tree limbs down.

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

A complex of severe storms moved eastward along the I-70 corridor during the early morning hours of May 19th. There were two tornadoes as well as numerous damaging wind reports with this event.

A weak tornado formed one mile east of Williamsburg, Missouri along Old US 40 at a residence and business where two barns were damaged and another was destroyed. Two vehicles were also flipped at this location. Debris was tossed up to one mile down the tornado's path into the adjacent farm field and tree line. The tornado then crossed County Road 1031, snapping a power pole. The tornado dissipated shortly after crossing County Road 1033. Overall, the tornado was rated EF1 with a path length of 1.58 miles. Maximum path width was 50 yards. No deaths or injuries were reported with this tornado.

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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 06:00 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 St Louis radar (KLSX), 89 km away, was scanning. The volume nearest the touchdown began at 09:13 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 2017 tornado in MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are

43 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.