EF1 tornado, Pacific Jct, Iowa, June 4, 2008

1. EF065 to 85 mph

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

2. EF186 to 110 mphthis tornado

   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

EF1

Date

June 4, 2008

Touchdown

6:04 PM CDT (23:04 UTC)

Lifted

6:15 PM CDT (23:15 UTC)

On the ground

11 minutes

Path length

4.8 miles (7.7 km)

Path width

220 yards (201 m)

Deaths

0

Injuries

0

County

Mills County

Touchdown point

40.938, -95.807

Lift-off point

41.007, -95.796

Record number

0806041704-01

A stationary front over Kansas started lifting north on June 4th as an unseasonably strong upper level low pressure system was organizing over the central Rockies. This allowed very warm and unstable air to feed north into southern Nebraska and southwest Iowa during the afternoon on the 4th. Severe thunderstorms developed by afternoon on June 4 over central Nebraska. The activity quickly developed and spread into eastern Nebraska and southwest Iowa through evening. A few tornado producing supercells developed over the area...and many of the storms produced very heavy rain which fell on soils that were saturated from significant rains recorded over the prior week.

A tornado touched down 5 miles south southeast of Pacific Jct and tracked to 1/2 mile south of town. The tornado caused scattered tree and farm outbuilding damage along its track.

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

24 minutes of warning. NWS OAX issued a tornado warning for this county at 22:40 UTC, 24 minutes before the tornado touched down, in force until 23:30 UTC.

The county was under a tornado watch, issued at 22:08 UTC and running to 01:50 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, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 20:01 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 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.

Plattsmouth (PMV), 10 km from the path, in the two hours either side.

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

The Omaha radar (KOAX), 61 km away, was scanning. The volume nearest the touchdown began at 22:59 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 2008 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

45 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.