EF0 tornado, Murphy, Nebraska, May 1, 2018

1. EF065 to 85 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   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

EF0

Date

May 1, 2018

Touchdown

4:35 PM CDT (21:35 UTC)

Lifted

4:37 PM CDT (21:37 UTC)

On the ground

2 minutes

Path length

0.0 miles (0.0 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$50,000

County

Hamilton County

Touchdown point

40.916, -98.145

Lift-off point

40.916, -98.145

Record number

1805011535-01

5 damage points were recorded along this path by NWS GID, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 75 mph.

• wood frame structure 2x4 came through house roof
• roof damage from flying debris
• overturned pivot end. Width 50 yards.

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

Severe storms produced numerous reports of hail and 3 brief, weak tornadoes on this Tuesday afternoon and evening. Between 230 and 330 PM CST, scattered fairly small supercell thunderstorms developed along a line from Red Cloud to Grand Island to Columbus. They were not mini-supercells, though, as cloud tops were near 40,000 ft. The storms generally remained along that line except for one storm that moved east into Clay County and another small multicell cluster that moved east along the Nebraska-Kansas border. Nearly 30 occurrences of severe hail were reported with most of between the sizes of quarters and golf balls. The largest hail reported was 2 inches in diameter in the town of Roseland. Three brief EF-0 tornadoes also occurred. The storms from Grand Island to Columbus formed along a slow-moving cold front. One tornado was associated with a supercell located on or very close to the front just west of Aurora. Another tornado formed near Doniphan as a north-northeastward-moving storm crossed the front. The third tornado occurred with the storm that moved east along the Nebraska-Kansas border. This storm evolved from a small bow echo and exhibited a spiral shape as it produced a brief tornado near Chester. The storms dissipated or moved out of south central Nebraska by 6 PM CST.||A low pressure system was near Lake Superior with a slow-moving cold front extending southwest across Nebraska to the Oklahoma Panhandle. In the upper-levels, southwest flow covered most of the U.S., with a trough over the West and a ridge over the Northeast. Just prior to thunderstorm development, temperatures were in the lower 80s with dewpoints in the upper 50s to near 60. With mid-level lapse rates near 8 C/km, MLCAPE was 2000-2500 J/kg. Deep layer shear was 40-50 kts, which was more than sufficient for supercell convective mode.

A nearly stationary landspout tornado occurred northwest of Aurora. This EF-0 tornado had a maximum wind speed estimated to be 70 MPH, which was based upon damage to a center irrigation pivot which was overturned. Several people witnessed this tornado.

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 tornado watch, issued at 19:48 UTC and running to 00:11 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 19:55 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.

Aurora (AUH), 13 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Grand Island radar (KUEX), 71 km away, was scanning. The volume nearest the touchdown began at 21:34 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

10 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.