F0 tornado, Downs to Cooksville, Illinois, April 30, 1997

1. F040 to 72 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. F173 to 112 mph

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

3. F2113 to 157 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. F3158 to 206 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. F4207 to 260 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. F5261 to 318 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

F0

Date

April 30, 1997

Touchdown

4:05 PM CDT (21:05 UTC)

Path length

14.5 miles (23.3 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$100,000

County

McLean County

Touchdown point

40.400, -88.830

Lift-off point

40.570, -88.680

Record number

711

As a strong area of low pressure moved into the Midwest, severe thunderstorms developed along and ahead of a cold front which moved through Central Illinois during the afternoon and early evening hours. There were numerous reports of trees, tree limbs, and power lines knocked down. Also, 6 tornadoes were reported across the area. Fortunately, only a few minor injuries were reported and no deaths occurred with these tornadoes.

A tornado first touched down 1.5 miles east of Downs, blowing down a barn which trapped a 32-year old pony for 16 hours. Several other barns, machine sheds, cattle sheds, and grain bins were damaged or destroyed in the area. As the tornado travelled to the northeast, it damaged a barn and grain bin 1 mile north of Holder and a cattle barn was destroyed 2.5 miles north of Holder on Route 9. Further to the northeast the tornado caused $100,000 in damage to a gas station in Cooksville where two of the three service bays were destroyed and the third one sustained some damage. The fire station and a golf cart business reported minor roof damage. Also, power poles just north of Cooksville were snapped off and others were leaning to the ground. Before the tornado lifted and dissipated, it damaged a large barn 3 miles northeast of Cooksville. No injuries were reported.

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

22 minutes of warning. NWS ILX issued a tornado warning for this county at 20:43 UTC, 22 minutes before the tornado touched down, in force until 21:30 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. The outlook in force was issued at 05:47 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.

Bloomington/Norm (BMI), 14 km from the path, in the two hours either side.

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

The Lincoln radar (KILX), 62 km away, was scanning. The volume nearest the touchdown began at 21:05 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.

The live radar over the trackEvery 1997 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.