EF1 tornado, Menominee to St James, Nebraska, June 29, 2017

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 29, 2017

Touchdown

5:45 PM CDT (22:45 UTC)

Lifted

6:11 PM CDT (23:11 UTC)

On the ground

26 minutes

Path length

14.4 miles (23.2 km)

Path width

150 yards (137 m)

Deaths

0

Injuries

0

County

Cedar County

Touchdown point

42.752, -97.406

Lift-off point

42.680, -97.152

Record number

1706291645-01

6 damage points were recorded along this path by NWS OAX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 107 mph.

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

During the afternoon and evening hours of June 29th, scattered severe thunderstorms formed over the mid Missouri Valley, along and ahead of a cold front moving into the region. The approach of an upper-air disturbance from the northwest in conjunction with a moderately unstable air mass yielded a favorable environment for supercells and other organized storm structures which produced a considerable amount of large hail.||One supercell produced a 14.4-mile long tornado in addition to hail up to baseball size while tracking across northern Cedar County in far northeast Nebraska. Later in the evening, another supercell moved across the Omaha metro area, also producing hail up to baseball size.

This tornado started about 4 1/2 miles northwest of Fordyce near Highway US 81 and moved southeast. The tornado crossed Nebraska Highway 12 and passed 1/2 mile north of Bow Valley. Little damage was noted as the tornado crossed through rural, agricultural, areas. The tornado made a right turn and headed south-southeast about 2 miles south of Wynot. The tornado struck a farmstead which destroyed a barn, knocked over trees, and did minor structural damage to a home. The tornado then flipped over a center pivot irrigation system and produced minor roof damage to a home before dissipating.

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 20:43 UTC and running to 00:56 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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:58 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 Sioux Falls radar (KFSD), 107 km away, was scanning. The volume nearest the touchdown began at 22:44 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 2017 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

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.