EF2 tornado, Decker to Willis, Indiana, May 26, 2024

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

May 26, 2024

Touchdown

9:49 PM EDT (01:49 UTC)

Lifted

10:00 PM EDT (02:00 UTC)

On the ground

11 minutes

Path length

12.1 miles (19.5 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$700,000

County

Knox County

Touchdown point

38.517, -87.523

Lift-off point

38.594, -87.321

Record number

2405261949-01

13 damage points were recorded along this path by NWS IND, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 112 mph.

• MINIMAL damage, tree topping mostly. RFD or funnel topping trees. Mobile home onsite no damage.
• Two utility poles snapped and leaning northwest into what appears to be weak circulation with tree topping.
• Well built metal farm building completely destroyed. Debris scattered to north and east northeast at least a mile. Bus was lifted and moved 10-20 yards with no visible ground scouring from tires. Narrow tornado about 30 yds wide.
• Looks like 2 small vortices with this tornado and thisbeing southern one

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

Two rounds of thunderstorms impacted central Indiana during the Sunday before Memorial day with a quick microburst in the morning followed by a QLCS tornado across Knox county followed by a swath of thunderstorm winds. Damage beyond Knox county was more widespread but not quite as intense as the EF-2 tornado.

The tornado with peak winds of 112 mph began near Decker where tree damage was found near the starting point. At the start, funnel clouds were jumping as most|of the damage was confined to the trees while houses remained|undamaged. The tornado quickly strengthened in producing low end|EF2 damage about a half mile east of Decker where a pole barn was|destroyed with debris found over a mile east of the original|damage location. In that same lot, a school bus was picked up and|moved about 20 yards away.||A sporadic damage path continued for about 2.5 miles northeast of|Decker with EF1 damage to mainly trees and one other small barn.|The sporadic damage path persisted through rural portions of|southern Knox County with EF0 tree and power line damage. About 3|miles southwest of Monroe City, the tornado hit another garage|structure, pushing in its bolted doors and causing the structure|to collapse. Debris from that structure was thrown about a mile|northeastward into a field, with drone footage capturing|circulations carved in the ground in that field. There were likely|a few circulations associated with the main tornado as additional|tree damage was found on the north side of this same property,|with no damage in between, leaving the house unaffected.||The tornado continued on its northeast path through southern Knox|County about a mile south of Monroe City, causing EF0 damage to|trees. The tornado lifted in rural portions of southeast Knox|County just prior to the Knox/Daviess County line.

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.

The county was under a tornado watch, issued at 23:55 UTC and running to 03:59 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 00:57 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.

Mount Carmel (AJG), 27 km from the path, in the two hours either side.

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

The Evansville,IN radar (KVWX), 42 km away, was scanning. The volume nearest the touchdown began at 01:51 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 2024 tornado in IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

69 more were confirmed in the United States that day.

All 70 of them

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.