Tornadoes · United States · Iowa · 2018
EF1 tornado, Alburnett, Iowa, September 25, 2018
This EF1 tornado ran 0.1 miles across Linn County on September 25, 2018, touching down at 1:30 PM CDT and reaching 20 yards wide. It killed nobody, and did $1,000 of property damage.
The rating scale
Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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.
The record
- Rating
- EF1
- Date
- September 25, 2018
- Touchdown
- 1:30 PM CDT (18:30 UTC)
- Lifted
- 1:31 PM CDT (18:31 UTC)
- On the ground
- 1 minutes
- Path length
- 0.1 miles (0.2 km)
- Path width
- 20 yards (18 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $1,000
- County
- Linn County
- Touchdown point
- 42.134, -91.619
- Lift-off point
- 42.134, -91.616
- Record number
- 1809251230-01
The damage survey
7 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 110 mph.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
What the Weather Service recorded
A line of strong storms tracked east across eastern Iowa during the afternoon hours. These storms produced several tornadoes and damaging wind gusts around 60 mph.
A NWS Survey Team determined a brief high end EF1 tornado, with estimated maximum wind speeds around 110 mph, snapped and uprooted hardwood trees at a farmstead. The tornado was embedded in a roughly quarter mile wide swath of straight line wind damage with estimated speeds of 80 to 90 mph.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
2 minutes of warning. NWS DVN issued a tornado warning for this county at 18:28 UTC, 2 minutes before the tornado touched down, in force until 18:57 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 17:48 UTC | 18:30 UTC | Severe Thunderstorm Warning | DVN |
| 18:28 UTC | 18:57 UTC | Tornado Warning | DVN |
| 18:28 UTC | 19:07 UTC | Severe Thunderstorm Warning | DVN |
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 forecast that day
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 16:25 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 air that afternoon
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.
Davenport, (KDVN), 12:00Z
6.5 hours before the tornado, 109 km from the path. September 25, 2018.
- Mixed-layer CAPE
- 47 J/kg
- Mixed-layer CIN
- -108 J/kg
- Surface CAPE
- 1 J/kg
- Mixed-layer LCL
- 703 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 4 m²/s²
- 0-3 km storm-relative helicity
- 38 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 3.7 K/km
Davenport, (KDVN), 00:00Z
5.5 hours after it, 109 km from the path. September 26, 2018.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -97203 J/kg
- Surface CAPE
- 105 J/kg
- Mixed-layer LCL
- 728 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- -92 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
- 0-3 km lapse rate
- 5.3 K/km
The radar
The Quad Cities radar (KDVN), 104 km away, was scanning. The volume nearest the touchdown began at 18:28 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.
What was reported nearby
Local storm reports within 60 km of the path, in the three hours either side.
| Time (UTC) | Report | Where | County | Remark |
|---|---|---|---|---|
| 18:22 UTC | TSTM WND GST 54 | Cedar Rapids Municipal | Linn, IA | |
| 18:24 UTC | TSTM WND GST 60 | Hiawatha | Linn, IA | |
| 18:26 UTC | TSTM WND GST 60 | 2 W Cedar Rapids | Linn, IA | |
| 18:29 UTC | TORNADO 1 | 1 S Alburnett | Linn, IA | A BRIEF HIGH END EF-1 TORNADO SNAPPED AND UPROOTED HARDWOOD TREES AT A FARMSTEAD 1 MILE SOUTH OF ALBURNETT. THE TORNADO WAS 20 YARDS WIDE ALONG ITS 0.12 MILE PATH WITH A PEAK ESTIMATED WIND SPEED OF 110 MPH. THE TORNADO |
| 18:36 UTC | TSTM WND DMG | S Alburnett | Linn, IA | SEVERAL HEALTHY LARGE TREE BRANCHES DOWN...TIME ESTIMATED FROM RADAR. |
| 18:47 UTC | TSTM WND GST 44 | Iowa City Municipal Air | Johnson, IA | |
| 18:53 UTC | TORNADO | 1 Ssw Mechanicsville | Cedar, IA | BRIEF TORNADO SOUTH OF TOWN. LOFTED 2 GRAIN BINS AND CAUSED DAMAGE TO SOME CORN. |
| 19:00 UTC | HEAVY RAIN 1.38 | 1 Ssw North Liberty | Johnson, IA | STORM TOTAL...RAIN FELL IN PAST 45 MINUTES. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2018 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are
The other tornadoes of September 25, 2018
7 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| September 25 | 1:26 PM CDT | EF0 | Henry, IA | 0.3 | 20 | |||
| September 25 | 1:53 PM CDT | EF0 | Cedar, IA | 0.1 | 20 | $3,000 | ||
| September 25 | 2:14 PM CDT | EF1 | Henry, IA | 1.1 | 200 | $2,000 | ||
| September 25 | 8:23 PM EDT | EF1 | Monroe, MI | 4.3 | 520 | $500,000 | ||
| September 25 | 8:45 PM EDT | EF0 | Monroe, MI | 4.1 | 250 | $300,000 | ||
| September 25 | 8:55 PM EDT | EF1 | Wayne, MI | 3.3 | 200 | $500,000 | ||
| September 25 | 11:53 PM CDT | EF1 | Fentress, TN | 0.5 | 50 | $15,000 |
What this means
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.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.