Tornadoes · United States · Illinois · 2024
Unrated tornado, Bolton, Illinois, March 4, 2024
This Unrated tornado ran 0.1 miles across Stephenson County on March 4, 2024, touching down at 1:59 PM CST and reaching 30 yards wide. It killed nobody.
The rating scale
Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
Unratedthis tornado
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.
The record
- Rating
- Unrated
- Date
- March 4, 2024
- Touchdown
- 1:59 PM CST (19:59 UTC)
- Lifted
- 2:00 PM CST (20:00 UTC)
- On the ground
- 1 minutes
- Path length
- 0.1 miles (0.2 km)
- Path width
- 30 yards (27 m)
- Deaths
- 0
- Injuries
- 0
- County
- Stephenson County
- Touchdown point
- 42.240, -89.780
- Lift-off point
- 42.240, -89.780
- Record number
- 2403041359-01
The damage survey
1 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry.
- Pictures and video from a storm chaser confirm a brief tornado southeast of Pearl City Monday afternoon. The Stephenson County Emergency Manager surveyed the area and did not see any damage. Therefore, the tornado is rated EF-Unknown.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
What the Weather Service recorded
Scattered storms developed during the afternoon of March 4th, with numerous storms throughout the area by the evening. Most storms produced small hail, with several storms producing upwards to one-inch hail or larger. The largest hail seen was golf ball-sized in northeast Missouri and southern Iowa. One brief tornado was also seen, southeast of Pearl City Illinois, with no damage observed.
Pictures and video from a storm chaser confirm a brief tornado southeast of Pearl City Monday afternoon. The Stephenson County Emergency Manager surveyed the area and did not see any damage. Therefore, the tornado is rated EF-Unknown.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 19:11 UTC | 19:45 UTC | Severe Thunderstorm Warning | DVN |
| 19:45 UTC | 20:30 UTC | Severe Thunderstorm Warning | DVN |
| 21:03 UTC | 21:45 UTC | Severe Thunderstorm Warning | DVN |
| 03:41 UTC | 04:05 UTC | Severe Thunderstorm Warning | DVN |
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 forecast that day
The Storm Prediction Center had this point in a Marginal Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 16:00 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 air that afternoon
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.
Davenport, (KDVN), 12:00Z
8.0 hours before the tornado, 91 km from the path. March 4, 2024.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -103283 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 1669 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- 41 m²/s²
- 0-3 km storm-relative helicity
- 126 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 3.0 K/km
Davenport, (KDVN), 00:00Z
4.0 hours after it, 91 km from the path. March 5, 2024.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -80572 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 829 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 171 m²/s²
- 0-3 km storm-relative helicity
- 304 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.5
- 0-3 km lapse rate
- 3.8 K/km
The radar
The Quad Cities radar (KDVN), 96 km away, was scanning. The volume nearest the touchdown began at 19:58 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.
What was reported nearby
Local storm reports within 60 km of the path, in the three hours either side.
| Time (UTC) | Report | Where | County | Remark |
|---|---|---|---|---|
| 19:29 UTC | HAIL 1 | 5 Sse Massbach | Carroll, IL | Delayed Report, Near intersection of Zion Rd and Elizabeth Rd, time estimated from radar. |
| 19:59 UTC | TORNADO | 3 W Bolton | Stephenson, IL | Pictures and video from a storm chaser confirm a brief tornado southeast of Pearl City Monday afternoon. The Stephenson County Emergency Manager surveyed the area and did not see any damage. Therefore, the tornado is rat |
| 20:32 UTC | HAIL 0.7 | 1 N Dakota | Stephenson, IL | pea to dime size hail began about 232 pm. |
| 20:46 UTC | HAIL 0.88 | Lake Summerset | Winnebago, IL | Multiple photos shared to social media show hail up to approximately nickel size in the Lake Summerset area. Time estimated by radar. |
| 21:05 UTC | HAIL 0.5 | 4 N Hitt | Carroll, IL | Report from mPING: Half-inch (0.50 in.). |
| 21:05 UTC | HAIL 1 | Lanark | Carroll, IL | Delayed report via social media. Lasted 10 minutes. |
| 21:05 UTC | HAIL 1 | Lanark | Carroll, IL | |
| 21:45 UTC | NON-TSTM WND GST 43 | Rockford Airport | Winnebago, IL | ASOS station KRFD Rockford Airport. |
| 22:15 UTC | HAIL 0.5 | 1 S Sterling | Whiteside, IL | Report from mPING: Half-inch (0.50 in.). |
| 22:15 UTC | HAIL 1 | 1 W Rock Falls | Whiteside, IL | Report from mPING: Quarter (1.00 in.). |
| 22:40 UTC | HAIL 0.7 | 1 Nnw Dixon | Lee, IL | Photo shared to social media shows dime size hail in Dixon. Time estimated by radar. |
| 22:48 UTC | HAIL 0.88 | Grand Detour | Ogle, IL | Public report of nickel size hail in Grand Detour. |
| 22:48 UTC | HAIL 1 | 1 N Grand Detour | Ogle, IL | Photo shared on social media showing quarter size hail near Grand Detour. |
| 22:48 UTC | HAIL 1 | 2 Nnw Dixon | Lee, IL | Trained spotter reports quarter sized hail on the north side of Dixon. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2024 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are
What this means
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.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.