EF0 tornado, Armstrong to Bismarck, Illinois, May 20, 2025

1. EF065 to 85 mphthis tornado

   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 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

EF0

Date

May 20, 2025

Touchdown

5:06 PM CDT (22:06 UTC)

Lifted

5:15 PM CDT (22:15 UTC)

On the ground

9 minutes

Path length

6.7 miles (10.7 km)

Path width

40 yards (37 m)

Deaths

0

Injuries

0

County

Vermilion County

Touchdown point

40.202, -87.844

Lift-off point

40.243, -87.729

Record number

2505201606-02

16 damage points were recorded along this path by NWS ILX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 98 mph.

• Tree damage on east side of road. no pic due to driving.

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

A warm front lifted slowly northward through central Illinois during the afternoon of May 20th. A few showers developed in the vicinity of the boundary...with one of the cells producing a brief EF-0 tornado near Oakland in northeastern Coles County. Meanwhile further west, scattered supercell thunderstorms formed in the warm sector ahead of a cold front crossing the Mississippi River. Some of the storms dropped hail as large as tennis balls (2.5 in diameter) across portions of Morgan County as they initially developed. As the storms continued further eastward, several weak tornadoes were observed: one near Latham in southeastern Logan County and four additional tornadoes further east across eastern Champaign County into Vermilion County. The strongest tornado was rated EF-1 as it snapped two power poles and damaged numerous trees near Armstrong and Potomac in Vermilion County. Further southeast, a downburst with estimated 90 mph winds created widespread wind damage on the south side of Westville in Vermilion County.

A tornado touched down along IL-49 midway between East 2700 North Road and East 2800 North Road about 3 miles south of Armstrong at 5:06 PM CDT. The tornado initially caused some tree damage, then tracked eastward and snapped two power poles along North 650 East Road. It then continued to near the intersection of East 2800 North Road and Potomac-Collison Road where it snapped or blew down around 12 large trees at a residence before dissipating shortly thereafter at 5:10 PM CDT.

A tornado touched down along East 2300 North Road just east of its intersection with North 500 East Road about 2.5 miles southwest of Collison at 5:06 PM CDT. The tornado initially caused minor tree damage, then tracked eastward where it was video taped by spotters as it passed 2 miles southeast of Collison. It then tracked northeastward through Horseshoe Bottom Nature Preserve and caused additional tree damage along East 2600 North Road before dissipating just northeast of the intersection of East 2600 North Road and North 1110 East Road at 5:15 PM CDT.

A tornado touched down southeast of the intersection of East 2800 North Road and North 2050 East Road about 3 miles east of Bismarck at 5:39 PM CDT. The tornado tracked northeastward, causing some tree damage along East 2800 North Road and damaging the roof of an outbuilding before dissipating northeast of IL-119 just shy of the Indiana border at 5:41 PM CDT.

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

19 minutes of warning. NWS ILX issued a tornado warning for this county at 21:47 UTC, 19 minutes before the tornado touched down, in force until 22:30 UTC.

The county was under a tornado watch, issued at 18:44 UTC and running to 01:00 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 19:52 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.

Danville (DNV), 16 km from the path, in the two hours either side.

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

The Lincoln radar (KILX), 132 km away, was scanning. The volume nearest the touchdown began at 22:07 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 2025 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

38 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.