EF2 tornado, Waterloo, Illinois, April 22, 2011

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

April 22, 2011

Touchdown

8:50 PM CDT (01:50 UTC)

Lifted

8:55 PM CDT (01:55 UTC)

On the ground

5 minutes

Path length

3.5 miles (5.7 km)

Path width

90 yards (82 m)

Deaths

0

Injuries

1

County

Monroe County

Touchdown point

38.349, -90.155

Lift-off point

38.340, -90.091

Record number

1104221950-01

A strong cold front moved through region. With plenty of moisture, instability and decent low level shear, severe storms developed along the Interstate 70 corridor in Missouri and Illinois. Numerous reports of large hail and 5 tornadoes occurred with this event. One of the tornadoes was a long track one that moved through the St. Louis metropolitan area with it being rated an EF4, with only a few minor injuries and no deaths. Also, quite a bit of rain fell during this event and caused flash flooding. The flash flooding persisted for several days as additional rounds of heavy rain fell over the same region through the 26th of April.

A tornado touched down on the north side of Waterloo, Illinois near the intersection of Leah Drive and James Street. Several homes and businesses sustained varying degrees of damage; from displaced roofing materials to businesses with structural damage. Two large air conditioners were tossed 30 yards from the roof of a business. Several large trees were snapped near the base of the trunk. Four power poles were snapped south of the intersection of North Market Street and Kolmer Avenue. One large garage was also destroyed behind a church with debris tossed southeastward 30 to 40 yards. The tornado skipped eastward and crossed Floraville Road on the north side of Ridge Club Golf Course then traveled down the first fairway. A number of cedar and pine trees were snapped. The tornado then crossed Ridge Road where several homes sustained minor roof damage, with 30 to 40 percent of the shingles removed. The tornado then traveled across the northern part of Konarcik Park. Numerous old growth pine trees were snapped at the base of the trunk. Trees three feet in diameter were common in this area. The tornado caused damage to the siding of one home near the intersection of Konarcik and Kopp Roads before lifting. There was one minor injury at Canterbury Manor Nursing Center due to flying glass when a window broke. The maximum intensity was low end EF2, with a maximum estimated wind speed of 115 mph. The maximum width of the tornado was 80 to 90 yards with a total path length of 3.5 miles.

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

29 minutes of warning. NWS LSX issued a tornado warning for this county at 01:21 UTC, 29 minutes before the tornado touched down, in force until 02:00 UTC.

The county was under a tornado watch, issued at 20:38 UTC and running to 03:00 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 Moderate Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 00:59 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.

Cahokia/St Louis (CPS), 25 km from the path, in the two hours either side.

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

The St Louis radar (KLSX), 63 km away, was scanning. The volume nearest the touchdown began at 01:50 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 2011 tornado in IllinoisEvery tornado in Illinois since 1950Warnings in force in Illinois nowThe forecast where you are

19 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.