EF0 tornado, Villisca to Sciola, Iowa, March 23, 2009

1. EF065 to 85 mphthis tornado

   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 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. 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

EF0

Date

March 23, 2009

Touchdown

7:56 PM CDT (00:56 UTC)

Lifted

7:58 PM CDT (00:58 UTC)

On the ground

2 minutes

Path length

1.9 miles (3.1 km)

Path width

440 yards (402 m)

Deaths

0

Injuries

0

County

Montgomery County

Touchdown point

41.007, -94.994

Lift-off point

41.034, -94.985

Record number

0903231856-01

An intense upper level low pressure system tracked from eastern Colorado into southeast South Dakota from March 23rd to March 24th. This caused a surface low pressure system to move from western Nebraska into southeast South Dakota during that time. As the low tracked northeast, a dry-line moved into eastern Nebraska during the afternoon of March 23rd. With surface temperatures in the 60s and 70s, and dewpoint temperatures in the 50s, ample instability was in place to allow a line of severe thunderstorms to develop as the dry-line punched eastward. Several fast moving and low-topped supercell thunderstorms were embedded in the line, and one cell produced cyclic tornadoes from southeast of Lincoln into western Iowa. The storms in the line were moving north northeast at between 50 and 60 mph. In addition to the severe weather, strong southerly gradient winds prevailed ahead of the low pressure. In some cases the winds gusted between 50 and 60 mph for several hours across parts of eastern Nebraska.

The tornado touched down just southwest of the intersection of 270th and Q Ave. west-southwest of Villisca. Near that point the roof was torn off of an outbuilding and an empty grain bin was blown across the road. A barn had some roof structure damage 2 to 3 miles north of there, near where the tornado apparently lifted.

The tornado touched down near Tenville destroying trees at a cemetery, causing house and farm outbuilding damage in the area and other tree and roof damage along its path. This tornado was from the same supercell that produced a tornado just to the south of here.

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

8 minutes of warning. NWS OAX issued a tornado warning for this county at 00:48 UTC, 8 minutes before the tornado touched down, in force until 01:15 UTC.

The county was under a tornado watch, issued at 20:52 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:42 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 Omaha radar (KOAX), 120 km away, was scanning. The volume nearest the touchdown began at 00:56 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 2009 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

18 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.