EF2 tornado, Wayland to Mooar, Missouri, December 4, 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 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mphthis tornado

   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

EF2

Date

December 4, 2017

Touchdown

5:13 PM CST (23:13 UTC)

Lifted

5:28 PM CST (23:28 UTC)

On the ground

15 minutes

Path length

8.0 miles (12.8 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

1

Property damage

$100,000

Crop damage

$4,000

Counties

Clark and Lee counties

Touchdown point

40.378, -91.627

Lift-off point

40.414, -91.489

Record number

1712041713-03

14 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 118 mph.

• A loaded semi truck was blown over and the driver was injured.

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

A storm system moved from Minnesota into Wisconsin during the afternoon and evenings hours of December 4th. This brought a cold front to along the Mississippi River by early evenings. Ahead of this cold front, scattered showers and thunderstorms moving northeastward across northeast Missouri. One of these storms produced damaging winds as it moved across Clark County. This storm also produced a tornado that caused EF-2 damage near the Highway 27 and 61 interchange before crossing the Des Moines River and moving into Iowa. One person was injured when the tornado hit a tractor trailer.

A storm system moved from Minnesota into Wisconsin during the afternoon and evenings hours of December 4th brought a cold front to along the Mississippi River by early evening. Ahead of this cold front, scattered showers and thunderstorms developed and moved northeastward from Missouri into southeastern Iowa. One of these storms produced a tornado that touched down southwest of Wayland Missouri and crossed the Des Moines River into Keokuk County Iowa. The tornado damaged trees before lifting shortly after crossing the river. The storm also produced some damaging winds as it moved across the city of Keokuk.

An NWS Storm Survey team found that an EF-2 tornado touched down in an open field southwest of Wayland, Missouri damaging trees and breaking windows. The tornado then moved east northeast over rural areas damaging trees. As the tornado approached Highway 27, it strengthened, causing EF-2 damage to power poles. The tornado hit a DOT facility, destroying doors and a salt shelter. When the tornado crossed the highway, a semi was overturned, causing one injury. The tornado crossed the Des Moines River into Iowa where it lifted. The peak estimated winds were 115 MPH.

An NWS Storm Survey team found that an EF-2 tornado touched down in an open field southwest of Wayland, Missouri damaging trees and breaking windows. The tornado then moved east northeast over rural areas damaging trees. As the tornado approached Highway 27, it strengthened, causing EF-2 damage to power poles. The tornado hit a DOT facility, destroying doors and a salt shelter. When the tornado crossed the highway, a semi was overturned, causing one injury. The tornado crossed the Des Moines River into Lee County Iowa where it caused EF-1 damage to trees before lifting about 1.1 miles north northeast of the river. The peak estimated winds along its entire path were 115 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.

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 19:37 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 Quad Cities radar (KDVN), 158 km away, was scanning. The volume nearest the touchdown began at 23:14 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

2 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.