EF1 tornado, Big Spgs, Nebraska, June 17, 2018

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 17, 2018

Touchdown

2:17 PM MDT (20:17 UTC)

Lifted

2:28 PM MDT (20:28 UTC)

On the ground

11 minutes

Path length

2.1 miles (3.4 km)

Path width

162 yards (148 m)

Deaths

0

Injuries

0

Property damage

$125,000

County

Deuel County

Touchdown point

41.070, -102.197

Lift-off point

41.077, -102.157

Record number

1806171417-01

17 damage points were recorded along this path by NWS LBF, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 100 mph.

• spruce tree other trees in the area upright still
• pig shed. 2X6s thrown into garage
• large outbuilding Larson farm
• empty tanks, travelling as far as one half mile. One bent over a fence.

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

Isolated thunderstorms developed over far northeastern Colorado mid afternoon on June 17th and tracked into Deuel where they became severe. Storms moved east northeast into the Sandhills and remained severe through the mid evening hours. Large hail, damaging winds and tornadoes were reported from Deuel county, east northeast into Blaine county.

A tornado touched down and damaged two farmsteads along its path. The first farmstead had a livestock shed which lost its roof. Wooden beams were tossed 30 yards, piercing the side of a garage. Shingles were ripped off of nearby outbuildings. The tornado then passed onto another farmstead where two full irrigation pivots were flipped, the first by the tornado, and a second by straight line winds. Large branches were also broken off of trees at this location.

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

9 minutes of warning. NWS LBF issued a tornado warning for this county at 20:08 UTC, 9 minutes before the tornado touched down, in force until 21:00 UTC.

The county was under a tornado watch, issued at 19:35 UTC and running to 02:40 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:52 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 North Platte radar (KLNX), 166 km away, was scanning. The volume nearest the touchdown began at 20:17 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 2018 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

4 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.