Tornadoes · United States · Nebraska · 2017

EF0 tornado, Boone, Nebraska, October 2, 2017

This EF0 tornado ran 0.3 miles across Boone County on October 2, 2017, touching down at 11:42 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
October 2, 2017
Touchdown
11:42 PM CDT (04:42 UTC)
Lifted
11:43 PM CDT (04:43 UTC)
On the ground
1 minutes
Path length
0.3 miles (0.5 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
County
Boone County
Touchdown point
41.602, -97.920
Lift-off point
41.606, -97.921
Record number
1710022242-01

The damage survey

3 damage points were recorded along this path by NWS OAX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 85 mph.

  • Grain bins and small outbuilding damaged. Two bins totally removed from site.
  • Several trees damage on east side of wooded area while other trees west of the highway were not damaged.
  • Tree damage primarily with large branches removed from upper portion of trees.

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

What the Weather Service recorded

An area of thunderstorms developed along a northeast to southwest frontal boundary in eastern Nebraska. One thunderstorm produced hail up to ping pong ball size in Monroe, Nebraska. Another thunderstorm produced a brief tornado northwest of St. Edward, later in the evening.

The National Weather Service in conjunction with local emergency management confirmed that a brief tornado occurred 2 3/4 miles northwest of St. Edward. The tornado damaged grain bins, a small farm outbuilding, trees and some crops.

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

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

Issued (UTC)ExpiredProductOffice
00:00 UTC07:02 UTCFlash Flood WatchOAX
01:00 UTC03:26 UTCSevere Thunderstorm WatchOAX

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 Marginal Risk. The outlook in force was issued at 00:57 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), 00:00Z

4.7 hours before the tornado, 133 km from the path. October 3, 2017.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2017-10-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 778 joules per kilogram, CIN -59, lifted condensation level 1536 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2017-10-03The 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 307 square meters per square second, 0 to 6 km bulk shear 49 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
778 J/kg
Mixed-layer CIN
-59 J/kg
Surface CAPE
791 J/kg
Mixed-layer LCL
1536 m above ground
0-6 km bulk shear
49 kt
0-1 km bulk shear
37 kt
0-1 km storm-relative helicity
307 m²/s²
0-3 km storm-relative helicity
383 m²/s²
Significant tornado parameter
0.7
Supercell composite
3.8
0-3 km lapse rate
5.6 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 12:00Z

7.3 hours after it, 133 km from the path. October 3, 2017.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2017-10-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 451 joules per kilogram, CIN -31, lifted condensation level 724 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2017-10-03The 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 346 square meters per square second, 0 to 6 km bulk shear 60 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
451 J/kg
Mixed-layer CIN
-31 J/kg
Surface CAPE
85 J/kg
Mixed-layer LCL
724 m above ground
0-6 km bulk shear
60 kt
0-1 km bulk shear
41 kt
0-1 km storm-relative helicity
346 m²/s²
0-3 km storm-relative helicity
369 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.4
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

The surface observations

Albion (BVN), 18 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
02:50 UTC59.458.520° 6 kt1008.8-VCTSRA
03:15 UTC59.258.320° 10 kt1008.5RA
03:35 UTC59.458.540° 11 kt171008.1-RA
03:55 UTC59.558.650° 11 kt181006.8-VCTSRA
04:15 UTC605980° 4 kt151006.8-RA
04:35 UTC60.8600° 0 kt1008.8+TSRA
04:55 UTC56.555.4330° 10 kt221009.5+VCTSRA
05:15 UTC56.755.4330° 10 kt1008.8-RA
05:35 UTC57.255.230° 7 kt1008.8-RA
05:55 UTC57.655.4310° 4 kt1009.1
06:15 UTC57.455.8310° 9 kt1010.2-RA
06:35 UTC57.256310° 12 kt1011.2-RA

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

The radar

The Omaha radar (KOAX), 133 km away, was scanning. The volume nearest the touchdown began at 04:40 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
04:42 UTCTORNADO 04 Nw St. EdwardBoone, NENATIONAL WEATHER SERVICE IN CONJUNCTION WITH REGION 44 EMERGENCY MANAGEMENT IDENTIFIED THE TRACK OF A BRIEF EF-0 TORNADO WITH A PATH LENGTH OF APPROXIMATELY 0.4 MILES...MAXIMUM WIDTH OF 20 YARDS AND A MAXIMUM WIND SPEED

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

This ground now

The live radar over the trackEvery 2017 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

The other tornadoes of October 2, 2017

7 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
October 26:53 PM CDTEF0Scott, KS4.5100
October 27:02 PM CDTEF1Scott, KS2.5150$150,000
October 27:09 PM CDTEF2Scott, KS18.3450
October 26:15 PM MDTEF0Greeley, KS0.7100
October 27:43 PM CDTEF1Gove, KS0.475$40,000
October 27:58 PM CDTEF0Gove, KS0.150$4,000
October 28:24 PM CDTEF1Gove, KS0.5100$75,000

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.