EF3 tornado, Low Pt to Evans, Illinois, February 28, 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 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 mphthis tornado

   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

EF3

Date

February 28, 2017

Touchdown

5:26 PM CST (23:26 UTC)

Lifted

5:50 PM CST (23:50 UTC)

On the ground

24 minutes

Path length

17.8 miles (28.6 km)

Path width

600 yards (549 m)

Deaths

0

Injuries

0

Property damage

$2.0 million

Counties

Marshall, Woodford and LaSalle counties

Touchdown point

40.913, -89.361

Lift-off point

40.985, -89.036

Record number

1702281726-01

88 damage points were recorded along this path by NWS ILX and NWS LOT, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF3. The highest wind the damage implies is 165 mph.

• grain bin blown into tree from foreground
• single story home destroyed
• gouge in ditch from debris and corn debris in the field even though no corn field near to west.
• Chaser video of brief tornado touchdown. No damage, on ground for less than 30 seconds.

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

An unseasonably warm and humid airmass was in place across central Illinois on February 28th...with afternoon high temperatures soaring to record levels in the upper 60s and lower 70s. Thanks to these extremely warm temperatures and dewpoints surging into the upper 50s and lower 60s, Convective Available Potential Energy (CAPE) values exceeded 1500J/kg across Missouri and the western half of Illinois by late afternoon. In addition, a strong mid-level jet streak enhanced 0-6km wind shear to an impressive 60-70kt. While the airmass within the warm sector was initially capped, an approaching upper wave helped weaken the cap and set the stage for strong to severe thunderstorms into the evening. As a cold front pushed across the Mississippi River, supercell thunderstorms initiated across west-central Illinois during the late afternoon and lingered into the evening. These storms produced a total of 4 tornadoes in the National Weather Service Lincoln County Warning Area (CWA), including an EF-3 tornado that touched down west of Washburn in Woodford County. Other storms produced scattered reports of large hail and damaging winds across the area.

A tornado touched down in an open field about 3.7 miles west of Washburn in extreme northern Woodford County at 5:26 PM CST. The tornado broke windows and did roof damage to a house and destroyed several outbuildings about a mile from its origin. The tornado rapidly widened to more than 1/4 mile across and increased in intensity to EF-3 as it destroyed a house about 2.5 miles west of Washburn. One mile to the east, the tornado tore the roof off a house before moving into Washburn. The tornado damaged 8 houses in town...doing significant damage to roofs, garages, automobiles, and trees before crossing into extreme southern Marshall County at 5:31 PM CST.

The tornado crossed from Woodford County into Marshall County at 5:31 PM CST. It tracked northeastward through southern Marshall County...destroying outbuildings and damaging house roofs and trees, as it widened to about 600 yards southwest of La Rose. The tornado weakened in southeast Marshall County as it crossed I-39 west of Rutland, then crossed into LaSalle County in the National Weather Service Chicago County Warning Area (CWA) at 5:49 PM CST.

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

21 minutes of warning. NWS ILX issued a tornado warning for this county at 23:05 UTC, 21 minutes before the tornado touched down, in force until 23:30 UTC.

The county was under a tornado watch, issued at 21:01 UTC and running to 03:58 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, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:56 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 Lincoln radar (KILX), 90 km away, was scanning. The volume nearest the touchdown began at 23:26 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 IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

29 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.