F0 tornado, Clutier, Iowa, May 10, 2003

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 10, 2003

Touchdown

6:27 PM CDT (23:27 UTC)

Path length

0.1 miles (0.2 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

County

Tama County

Touchdown point

42.080, -92.400

Lift-off point

42.080, -92.400

Record number

826

A very intense spring storm system developed over the central Plains and moved east, then northeast across Kansas into eastern Iowa. The low deepened to 986 mb by 06z of the 11th as it passed over La Crosse, WI. A southerly low level jet of 40 to 55 kts developed ahead of the storm system. A warm front extended east from the low and served as a focusing point for thunderstorm development early on, while a dry line extended south from the low lead to the development of a line of severe thunderstorms. Dew point temperatures in the warm sector soared into the upper 60s to mid 70s with temperature readings in the 80s. Dew point values at the 850 mb level were in the 14 to 17 degree C. range. By mid day, CAPE values over eastern KS into western MO were around 5000 J/kg with lifted indices around -11 C. Thunderstorms developed explosively by the mid afternoon hours. For the most part, severe weather from the storms in Iowa was in the form of Hail as most of the activity was north of the warm front. Parts of central into northeast Iowa received golf ball to larger than baseball size hail. The hardest hit area was in Poweshiek County in the Grinnell area, where 3 inch diameter hail caused considerable damage. There were scattered reports of nickel to ping pong ball size hail from Interstate 35 east. A few tornadoes occurred close to the triple point of the storm system. One tornado touched down in Marion County southwest of Attica and moved into Mahaska County northwest of Leighton. The track was generally through open countryside with little damage reported. One trailer was overturned east of Columbia near the beginning of the intermittent track of the tornado. Another brief touchdown was reported in Tama County near Clutier. No damage was reported with this tornado.

Brief touchdown in open area.

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

5 minutes of warning. NWS DMX issued a tornado warning for this county at 23:22 UTC, 5 minutes before the tornado touched down, in force until 23:45 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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 12:05 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.

Vinton (VTI), 35 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), 116 km away, was scanning. The volume nearest the touchdown began at 23:28 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 2003 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

50 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.