Tornadoes · United States · Nebraska · 2011

EF0 tornado, Ewing, Nebraska, August 18, 2011

This EF0 tornado ran 0.0 miles across Holt County on August 18, 2011, touching down at 5:23 PM CDT and reaching 20 yards wide. It killed nobody.

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.

  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.

The record

Rating
EF0
Date
August 18, 2011
Touchdown
5:23 PM CDT (22:23 UTC)
Lifted
5:24 PM CDT (22:24 UTC)
On the ground
1 minutes
Path length
0.0 miles (0.0 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
County
Holt County
Touchdown point
42.285, -98.350
Lift-off point
42.284, -98.349
Record number
1108181623-01

What the Weather Service recorded

Several intense severe thunderstorms developed on the afternoon of August 18th over north central Nebraska. These storms became anchored on a boundary which resulted in slow storm motions and enhanced the rotation in the storms. Very large hail up to baseball size fell from these storms, while they also produced funnel clouds and tornadoes near Ewing (eastern Holt county). In addition, another isolated thunderstorm dropped ping pong size hail over northwest Cherry county in the early evening hours.

There was a brief tornado touchdown just north of Ewing. As the storm moved over Ewing the entire storm exhibited massive rotation. No damage occurred from this tornado and it was rated as an EF0 tornado.

A tornado touched down just southeast of Ewing near the Holt county and Antelope county line. It was on the ground for one minute with no damage observed. At the time of the report, the tornado was large and was becoming rain wrapped.

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

The warnings

4 minutes of warning. NWS LBF issued a tornado warning for this county at 22:19 UTC, 4 minutes before the tornado touched down, in force until 22:45 UTC.

Issued (UTC)ExpiredProductOffice
21:43 UTC22:30 UTCSevere Thunderstorm WarningLBF
21:54 UTC23:00 UTCSevere Thunderstorm WarningLBF
22:19 UTC22:45 UTCTornado WarningLBF
22:25 UTC23:15 UTCSevere Thunderstorm WarningLBF
22:53 UTC23:30 UTCTornado WarningLBF
23:48 UTC03:50 UTCTornado WatchLBF

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 19:44 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.

Omaha, NE (KOAX), 12:00Z

10.4 hours before the tornado, 196 km from the path. August 18, 2011.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2011-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1181 joules per kilogram, CIN -126, lifted condensation level 683 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Omaha, NE at 12:00Z on 2011-08-18The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 234 square meters per square second, 0 to 6 km bulk shear 47 knots.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
1181 J/kg
Mixed-layer CIN
-126 J/kg
Surface CAPE
273 J/kg
Mixed-layer LCL
683 m above ground
0-6 km bulk shear
47 kt
0-1 km bulk shear
20 kt
0-1 km storm-relative helicity
234 m²/s²
0-3 km storm-relative helicity
385 m²/s²
Significant tornado parameter
0.0
Supercell composite
11.7
0-3 km lapse rate
3.9 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

1.6 hours after it, 196 km from the path. August 19, 2011.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2011-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1385 joules per kilogram, CIN -135, lifted condensation level 582 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Omaha, NE at 00:00Z on 2011-08-19The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 289 square meters per square second, 0 to 6 km bulk shear 66 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
1385 J/kg
Mixed-layer CIN
-135 J/kg
Surface CAPE
295 J/kg
Mixed-layer LCL
582 m above ground
0-6 km bulk shear
66 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
289 m²/s²
0-3 km storm-relative helicity
636 m²/s²
Significant tornado parameter
0.0
Supercell composite
47.4
0-3 km lapse rate
4.2 K/km

Open this sounding in Storm Lab

The surface observations

O Neill (ONL), 35 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:35 UTC78.869.8100° 14 kt191010.5
20:55 UTC80.669.8100° 14 kt201010.2
21:15 UTC80.671.6100° 7 kt1010.2
21:35 UTC80.671.6100° 11 kt161009.8VCTS
21:55 UTC80.671.690° 15 kt181009.5
22:15 UTC80.671.690° 13 kt1008.8VCTS
22:35 UTC80.671.680° 15 kt181009.1TS
22:55 UTC80.671.660° 15 kt181009.5VCTS
23:15 UTC78.869.850° 10 kt1009.5VCTS
23:35 UTC78.869.870° 11 kt1008.8VCTS
23:55 UTC78.869.8110° 9 kt1008.5TS
00:15 UTC7769.890° 18 kt221008.5VCTS

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

The radar

The North Platte radar (KLNX), 187 km away, was scanning. The volume nearest the touchdown began at 22:22 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)ReportWhereCountyRemark
21:43 UTCHAIL 13 Se InmanHolt, NEHAIL FALLING AT THE TIME OF THE REPORT.
22:01 UTCHAIL 22 N EwingHolt, NE
22:09 UTCHAIL 21 E EwingHolt, NE
22:13 UTCHAIL 1.55 Sse BristowHolt, NE
22:13 UTCHAIL 2.51 N EwingHolt, NEGOLF BALL TO TENNIS BALL SIZE HAIL ALONG HIGHWAY 45B.
22:13 UTCTORNADO3 Se EwingHolt, NELARGE TORNADO SPOTTED NEAR THE COUNTY LINE BECOMING RAIN WRAPPED.
22:15 UTCFUNNEL CLOUD3 Nnw EwingHolt, NEINITIAL FUNNEL CLOUD DISSIPATED WITH ANOTHER FORMING.
22:23 UTCTORNADO1 N EwingHolt, NEFUNNEL CLOUD BRIEFLY TOUCHED DOWN AND THEN WENT RIGHT BACK UP. THE STORM WAS EXHIBITING MASSIVE ROTATION OVER EWING.
22:45 UTCHAIL 1.7514 Ne OneillHolt, NE
22:46 UTCTORNADO3 W ClearwaterAntelope, NETORNADO ABOUT 3 MILES WEST OF CLEARWATER ON THE GROUND ABOUT ONE MILE. EVENT TIME ESTIMATED 546 PM TO 550 PM.
22:48 UTCTORNADO3 Se EwingHolt, NELARGE TORNADO SPOTTED NEAR THE COUNTY LINE BECOMING RAIN WRAPPED.
23:03 UTCTORNADOClearwaterAntelope, NE
23:06 UTCHAIL 2.754 Nne PageHolt, NE
23:20 UTCHAIL 1.759 N OrchardKnox, NE
23:30 UTCTORNADOClearwaterAntelope, NE
23:45 UTCHAIL 1OakdaleAntelope, NELASTED 15 MINUTES.
00:23 UTCHAIL 0.88TildenAntelope, NE

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2011 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

The other tornadoes of August 18, 2011

5 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 1810:15 AM EDTEF0New Hanover, NC0.320$3,000
August 185:35 PM EDTEF0Alexander, NC0.4150$500,000
August 185:46 PM CDTEF0Antelope, NE1.2100
August 185:48 PM CDTEF0Holt, NE0.450
August 186:40 PM MDTEF0Cherry, NE0.020

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.