EF1 tornado, Dundee to Edgewood, Iowa, June 16, 2014

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 16, 2014

Touchdown

9:33 PM CDT (02:33 UTC)

Lifted

9:55 PM CDT (02:55 UTC)

On the ground

22 minutes

Path length

12.6 miles (20.3 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$100,000

County

Delaware County

Touchdown point

42.551, -91.609

Lift-off point

42.637, -91.398

Record number

1406162033-01

6 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 105 mph.

• Reduced wind speed due to lack of corroborative impacts.
• Also several trees snapped off, one grain bin destroyed, two severely damaged.
• Lowered wind speed due to quality of construction (modular home) and nearby damage. Two small, old silos also blown over.
• Appeared that wind lifted roof from ridgeline causing roof to buckle and framing to snap or collapse. Door directly exposed to the wind did NOT collapse in, while nearby collateral damage suggested this lower wind speed.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

A warm front extended from eastern Nebraska to western Illinois and was lifting northward on June 16-17, 2014. An extremely unstable air mass was over the area on June 16 along with strong deep layer shear. This allowed scattered supercells to form during the afternoon and evening which produced two tornadoes, very large hail and damaging winds. A weak tornado formed 4 miles south of Lamont, Iowa in Buchanan County, tracked about 1 mile to the northeast before crossing into Delaware County. In Delaware County the tornado continued for about 13 miles to the northeast to Edgewood, Iowa. Another weak tornado briefly touched down in Benton County, Iowa. Strengthening mid level winds along with a strong low level jet in place later in the evening and overnight on June 17 produced widespread damaging winds of 60 to 70 mph. Strong warm air advection triggered more severe thunderstorms during the late evening of June 17.

A tornado formed 4 miles south of Lamont, IA in Buchanan County, tracked about 1 mile to the northeast before crossing into Delaware County. In Delaware County the tornado continued for about 13 miles to the northeast to Edgewood, IA. ||This entry is for the Delaware County portion of the tornado track (second and final segment).||Most of the damage was south and east of Dundee into south Edgewood. Several grain bins collapsed or were destroyed. Two old hog confinements were seriously damaged along with an aluminum roof being torn off. Numerous trees were snapped along the path.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

The county was under a severe thunderstorm watch, issued at 02:01 UTC and running to 04:19 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 01:14 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 Quad Cities radar (KDVN), 133 km away, was scanning. The volume nearest the touchdown began at 02:32 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 2014 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

35 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.