F0 tornado, Chillicothe, Iowa, May 15, 1998

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

May 15, 1998

Touchdown

4:15 PM CDT (21:15 UTC)

Path length

0.1 miles (0.2 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

County

Wapello County

Touchdown point

41.080, -92.520

Lift-off point

41.080, -92.520

Record number

965

As the system mentioned above continued to evolve, a widespread outbreak of severe weather took place over Iowa. Strong upper level dynamics moved over the state over the top of an unstable air mass. Surface dew point temperatures were in the low 70s with actual temperatures in the upper 70s to low 80s. CAPE values rose to between 2500 and 3500 J/kg. The situation became complex during the afternoon as several bands of severe thunderstorms developed. Some areas of the state were affected three times during the day as the storms raced northeast around 60 MPH. The main severe feature with the storms was high wind. There were numerous reports of wind gusts of 60 to 75 MPH. Some were even higher. One of the highest reports came from Atlantic in Cass County. Ninety one MPH winds there threw several cars and a few semi-tractortrailer trucks off of Interstate 80. High winds in Kossuth County at Algona resulted in roof damage at a nursing home there. Part of the roof was removed by the winds with the damage estimates to the building places at around $200,000. Another cluster of storms moved into north central Iowa and caused widespread damage in Cerro Gordo and Worth Counties. Both were hit with winds around 70 MPH. There were numerous other reports of damage to farm buildings around the state ranging from corn cribs damaged to barns being destroyed. Damage to trees and power lines was extensive. North of Algona, along U.S. Highway 169, seventy eight power poles were downed by the high winds resulting in a four day closure of the highway. Utility damage around the county was estimated at between $600,000 and $800,000, while insurance adjusters estimated damage around the county at $1.2 million. There were some reports of hail, especially during the first few hours of the event. The largest hail was around golf ball in size. In addition to the wind and hail, there were several tornado touch downs in the state. A tornado touched down in Kossuth County and did over $1 million in damage. The tornado destroyed 2 houses with another 10 sustaining major damage. Fifteen farmsteads were destroyed as well. Kossuth County was later declared a disaster area. There was also considerable damage to barns and other farm buildings across the county. The outflow from the tornadic storm in Kossuth County pushed an 85 MPH wind gust south into Humboldt County. The high winds blew over 41 railroad cars of the Union Pacific Railroad south of Ottosen. A band of 80 to 90 MPH winds swept across Franklin and Butler Counties. Damage was widespread. There was one report of the wind carrying the family dog over one half mile from home. The dog was later found safe and healthy. Another of the stronger tornadoes included one in Wright County that was on the ground for over 10 miles. It damaged several farm buildings along its path. Several 2 x 4's were driven into the ground north of Clarion by the tornado. Another fairly strong tornado touched down in Crawford County. The rope tornado touched down southeast of Denison. It hit a train about 3 miles east of Denison and derailed nine cars of the Union Pacific freight train. The engineer saw it coming and thought it was so small that nothing would happen. There was also minor damage to 1 house and several out buildings. There were a few other brief touch downs around the state, however no damage was reported with them. The rapid movement of the storms prevented a lot of the flooding that would have otherwise occurred. Repeat thunderstorms passing over Kossuth County did cause some urban flooding. Damage was relatively minor, however several homes reported minor flooding. As the storms moved across Hancock County, lightning struck a house in the town of Britt. The kitchen sink was blown away from the wall and all of the appliances and the electrical equipment in the house was damaged. Lightning struck very close to another house in Wright County in Belmond. A 75-year old woman received minor injuries as she was struck by lightning as she unplugged her TV near a large window.

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

2 minutes of warning. NWS DMX issued a tornado warning for this county at 21:13 UTC, 2 minutes before the tornado touched down, in force until 21:45 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. The outlook in force was issued at 11:01 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 live radar over the trackEvery 1998 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

25 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.