F1 tornado, Sharon Center to Hills, Iowa, April 13, 2006

1. F040 to 72 mph

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

2. F173 to 112 mphthis tornado

   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

F1

Date

April 13, 2006

Touchdown

8:38 PM CDT (01:38 UTC)

Path length

5.1 miles (8.2 km)

Path width

700 yards (640 m)

Deaths

0

Injuries

0

Property damage

$70,000

County

Johnson County

Touchdown point

41.600, -91.480

Lift-off point

41.670, -91.480

Record number

357

Tornado developed near the intersection of Sharon Center Rd (or W62) and 530th Street at 1916 CST. The tornado traveled east northeast and dissipated one half mile east of F62 and Lackender Avenue at 1922 CST. A continous damage path was noted with tree damage and some farm outbuildings damaged.

Tornado developed at the intersection of highways 1 & 218 on the southwest side of Iowa City at 1929 CST and tracked northeast through the city before lifting just northeast of the intersection of 1st Avenue & Hickory Trail at 1937 CST. This path took it through the southeast corner of the University of Iowa campus. This was the first tornado to hit near the campus in 35 years and the University was closed on Friday April 14th for safety reasons.The KIOW ASOS at the airport on the southwest side of the city recorded a peak wind gust of 49 knots (57 mph) at 1931 CST. This gust was likely the result of the rear flank downdraft as the tornado neared the intersection of U.S. 6 and highway 1 northeast of the airport. Hard times for the location of the tornado are 1930 CST at the Wal-Mart. At 1932-1933 CST power was lost at the Johnson County Sheriff Office with telephone lines, LAN, and automated systems going down as the tornado passed over the building. While the tornado was passing over the sheriff's office, someone flipped the outdoor warning sirens from automatic to manual override and activated the sirens one final time.Damage totals are still being evaluated and the $12 million amount will likely be closer to $15 million or possibly higher. Known damage amounts include; Iowa City and Johnson County $4 million with an additional $755,000 of uninsured loses (traffic lights, signs, street lights), University of Iowa $6 million with the motor pool headquarters a total loss and 31 vehicles damaged, and $1.3 million in damage to residences/businesses. Three automobile dealerships were damaged; one dealership had 200 vehicles damaged, a second had 60-70 vehicles damaged, and a third had nearly every vehicle sustaining some type of damage.A total of 1,016 residential and 35 commercial buildings were damaged with some destroyed. Some well known landmark buildings known to citizens, college students, and alumni were lost or heavily damaged. These included the Dairy Queen (lost) and St. Patrick's Church (heavily damaged). Several historic buildings were damaged downtown and it is unknown whether or not they can or will be saved. The tornado damaged the Alpha Chi Omega sorority house and damaged many student apartments located just off the campus on Iowa, Dodge, and Governor streets.Given the strength and width of the tornado it is amazing that only 30 injuries (many minor) occurred. Many U of I students were unaware of what was happening or dashed to a nearby parking garage for safety with the tornado approaching a few blocks behind them. Several foreign exchange students, many of whom had never seen, experienced, or heard of a tornado, were in awe and disbelief over the magnitude of the event. At St. Patrick's Church, the Maundy Thursday evening service had just ended. Upon being told of an approaching tornado by Decon Jerome Miller, the Reverend Rudolph Juarez ushered 50 to 75 parishioners (many elderly) to the safety of the rectory basement next door. This action saved the lives of everyone as the tornado tore off the roof off the church and collapsed the top portion of the brick facade and the steeple into the main congregation area.

Tornado began near the intersection of Taft Avenue and 480th Street at 1938 CST and moved east northeast. The tornado crossed U.S. 6 one mile east of its intersection with X14. At this point, the tornado turned to the left and traveled north crossing the Iowa Interstate Railroad and dissipated southeast of the intersection of Wapsi Avenue and 400th Street at 1948 CST.When this tornado cross the IAIS tracks and F46, it just missed traveling through a natural gas tank farm and the 15 pipelines feeding into it.A mobile home was destroyed and a house lost a portion of its roof. Considerable tree damage was noted and several farm outbuildings were damaged or unroofed.

Tornado developed 4.1 miles southeast of Lone Tree at 1945 CST and moved east southeast for 0.5 miles before crossing into Muscatine County at 1946 CST. The tornado continued east southeast in Muscatine County before turning left and dissipating southeast of Adams at 2002 CST. While in Johnson County tree and outbuilding damage was noted.

Tornado developed 2.9 miles east of Lone Tree at 1948 CST and moved east southeast 0.3 miles before crossing into Muscatine County at 1949 CST. Once in Muscatine County, the tornado continued east southeast and moved through the town of Nichols before turning left and dissipated 1 mile northeast of Nichols at 1956 CST.In Johnson County, tree damage was noted with an outbuilding damaged.

Tornado developed near the intesection of F46 and 420th Street at 2019 CST and moved southeast. It caused roof damage to a house. Ironically the same house had been damaged about 30 minutes earlier by the first tornado northeast of Hills.

Rated F1

Rated very high F2 with winds estimated at 155 mph.

Rated high F1

crossed into Muscatine county

Crossed into Muscatine County

Rated F1

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

40 minutes of warning. NWS DVN issued a tornado warning for this county at 00:58 UTC, 40 minutes before the tornado touched down, in force until 02:00 UTC.

The county was under a severe thunderstorm watch, issued at 22:33 UTC and running to 03:41 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 01:00 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 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.

The Quad Cities radar (KDVN), 75 km away, was scanning. The volume nearest the touchdown began at 01:37 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 2006 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

17 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.