F1 tornado, Mt Etna, Iowa, April 8, 2001

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 8, 2001

Touchdown

10:49 PM CDT (03:49 UTC)

Path length

1.0 miles (1.6 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

1

Property damage

$100,000

County

Adams County

Touchdown point

41.130, -94.730

Lift-off point

41.130, -94.720

Record number

621

Following the passage of the powerful storm system earlier in the weekend, another round of severe weather was on tap for the state. The cold front from the previous storm did not move all that far to the south of Iowa. As a result, warm and moist air was able to move north into Iowa rapidly. A warm front lifted into southern Iowa during the late afternoon hours, sending temperatures into the 80s over parts of southern Iowa. Dew point temperatures jumped into the low to mid 60s. The atmosphere became very unstable with thunderstorms developing along the front. Most of the storms were associated with the warm front itself, though a mesoscale feature moved along the front setting the stage for an additional like of thunderstorms that developed north to south in south central Iowa. The main feature with the storms was hail. There were numerous reports of hail ranging from nickel size up to golf ball size. Several of the storms had well developed meso circulations associated with them. A few tornadoes resulted. Two of the tornadoes were very small and only touched down briefly in Tama and Dallas Counties. The other tornadoes were stronger. One tornado touched down in Decatur County near Leon. Two people were injured, one requiring hospitalization, as a mobile home was overturned by the gust front ahead of the storm itself. The second of the stronger tornadoes moved through Adams County. A trailer house was overturned and the roofs were removed from two sheds on a farm northeast of Mt. Etna. Thunderstorms produced very heavy rainfall of one to two inches per hour over Ringgold County. Total rainfall approached 4 inches in less than 3 hours as storms repeatedly moved across the same areas. The rain caused flash flooding in the county. In one instance, Lotts Creek overtopped a road southeast of Mt. Ayr, causing nearly $50,000 in damage as the road washed out. As the storms moved through Decatur County, lightning stuck a house in Garde Grove. The house was set on fire, but it was not detected for several hours after the lightning strike. The house was destroyed and completely burned to the ground.

Trailer house overturned and destroyed. Roofs torn off of two sheds.

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.

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 00:47 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.

Creston (CSQ), 33 km from the path, in the two hours either side.

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

The Des Moines radar (KDMX), 107 km away, was scanning. The volume nearest the touchdown began at 03:47 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 2001 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

5 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.