Tornadoes · United States · Iowa · 2016
EF2 tornado, Norway to Fairfax, Iowa, July 17, 2016
From Norway to Fairfax, this EF2 tornado ran 4.0 miles across Benton and Linn counties on July 17, 2016, touching down at 5:15 AM CDT and reaching 75 yards wide. It killed nobody and injured 4, and did $275,000 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 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
EF2111 to 135 mphthis tornado
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
- EF2
- Date
- July 17, 2016
- Touchdown
- 5:15 AM CDT (10:15 UTC)
- Lifted
- 5:21 AM CDT (10:21 UTC)
- On the ground
- 6 minutes
- Path length
- 4.0 miles (6.4 km)
- Path width
- 75 yards (69 m)
- Deaths
- 0
- Injuries
- 4
- Property damage
- $275,000
- Crop damage
- $15,000
- Counties
- Benton and Linn counties
- Touchdown point
- 41.891, -91.897
- Lift-off point
- 41.877, -91.822
- Record number
- 1607170415-01
The damage survey
15 damage points were recorded along this path by NWS DVN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 115 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 nearly stationary frontal boundary spawned a line of thunderstorms that produced numerous reports of damaging winds and isolated tornadoes.
A tornado touched down southeast of Norway and tracked southeast to Walford and then into Linn County. It damaged 2 farmsteads before reaching Walford. In Walford, it damaged the roofs of numerous homes.
A tornado from Benton County continued southeast through southeastern portions of Walford. The tornado damaged the roofs of numerous homes. One home was completely destroyed when it collapsed on itself, apparently aided by wind blown debris.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 09:37 UTC | 10:30 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 05:59 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), 00:00Z
10.3 hours before the tornado, 116 km from the path. July 17, 2016.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -72488 J/kg
- Surface CAPE
- 197 J/kg
- Mixed-layer LCL
- 1263 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- 71 m²/s²
- 0-3 km storm-relative helicity
- 182 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 6.1 K/km
Davenport, (KDVN), 12:00Z
1.7 hours after it, 116 km from the path. July 17, 2016.
- Mixed-layer CAPE
- 865 J/kg
- Mixed-layer CIN
- -102 J/kg
- Surface CAPE
- 540 J/kg
- Mixed-layer LCL
- 981 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 310 m²/s²
- 0-3 km storm-relative helicity
- 332 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 2.3
- 0-3 km lapse rate
- 5.1 K/km
The radar
The Quad Cities radar (KDVN), 110 km away, was scanning. The volume nearest the touchdown began at 10:15 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 |
|---|---|---|---|---|
| 09:55 UTC | TSTM WND DMG | S Vinton | Benton, IA | ROOF BLOWN OFF A LARGE APARTMENT BUILDING AND A HOUSE DAMAGED. TIME ESTIMATED FROM RADAR. |
| 10:10 UTC | TSTM WND DMG | 2 E Palo | Linn, IA | REPORT WAS DELAYED....SPOTTER OBSERVED POWER FLAHES AROUND 510 AND THIS MORNING THERE WERE POWER LINES DOWN IN THE AREA WITH THE POWER OUT. |
| 10:15 UTC | TSTM WND GST 61 | W Cedar Rapids | Linn, IA | KCRG EQUIPMENT MEASUREMENT AT XAVIER HIGH SCHOOL ON THE WEST SIDE OF CEDAR RAPIDS. TIME OF THE EVENT IS ESTIMATED SINCE EXACT TIME IS UNKNOWN. |
| 10:25 UTC | TSTM WND GST 55 | 1 Sse Cedar Rapids | Linn, IA | 50 TO 55 MPH GUSTS. |
| 10:30 UTC | HAIL 0.25 | Swisher | Johnson, IA | |
| 10:46 UTC | TSTM WND DMG | Walford | Benton, IA | MULTIPLE HOMES DAMAGE IN WALFORD WITH ONE COLLAPSED. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2016 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are
The other tornadoes of July 17, 2016
9 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| July 17 | 4:58 AM CDT | EF2 | Benton, IA | 1.6 | 100 | 5 | ||
| July 17 | 6:03 AM CDT | EF1 | Jackson, IA | 1.0 | 50 | $5.0 million | ||
| July 17 | 6:27 AM CDT | EF0 | Scott, IA | 1.9 | 10 | |||
| July 17 | 6:36 AM CDT | EF1 | Scott, IA | 2.1 | 100 | |||
| July 17 | 8:30 AM CDT | EF0 | Galveston, TX | 0.0 | 20 | |||
| July 17 | 4:00 PM MDT | EF0 | Bernalillo, NM | 0.0 | 5 | |||
| July 17 | 8:18 PM CDT | EF0 | Putnam, IL | 1.2 | 25 | |||
| July 17 | 8:24 PM CDT | EF0 | Putnam, IL | 0.2 | 25 | |||
| July 17 | 9:41 PM CDT | EF1 | Kankakee, IL | 2.2 | 100 |
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.