Tornadoes · United States · Michigan · 2017

EF0 tornado, Kewadin, Michigan, August 3, 2017

This EF0 tornado ran 0.1 miles across Antrim County on August 3, 2017, touching down at 6:10 PM EDT and reaching 55 yards wide. It killed nobody, and did $55,000 of property damage.

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 3, 2017
Touchdown
6:10 PM EDT (22:10 UTC)
Lifted
6:11 PM EDT (22:11 UTC)
On the ground
1 minutes
Path length
0.1 miles (0.1 km)
Path width
55 yards (50 m)
Deaths
0
Injuries
0
Property damage
$55,000
County
Antrim County
Touchdown point
44.928, -85.381
Lift-off point
44.927, -85.381
Record number
1708031610-01

The damage survey

5 damage points were recorded along this path by NWS APX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 80 mph.

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

Thunderstorms moved into northern lower Michigan in the afternoon and evening of the 3rd. Isolated severe weather occurred, including a brief tornado.

An EF0 tornado crossed Williams Drive at the south end of Birch Lake, then dissipated over the lake. Maximum wind speed was estimated at 80 mph. Many trees were uprooted in the area, and a few homes were damaged by falling trees. Saturated soils likely contributed to the number of uprooted trees.

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. One was issued for the county at another hour that day.

Issued (UTC)ExpiredProductOffice
22:14 UTC22:45 UTCTornado WarningAPX

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 General Thunderstorms Risk. The outlook in force was issued at 19:54 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.

Green Bay/Straub, WI (KGRB), 12:00Z

10.2 hours before the tornado, 221 km from the path. August 3, 2017.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 12:00Z on 2017-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -101925, lifted condensation level 721 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Green Bay/Straub, WI at 12:00Z on 2017-08-03The 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 190 square meters per square second, 0 to 6 km bulk shear 28 knots.193958Sfc1 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
0 J/kg
Mixed-layer CIN
-101925 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
721 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
190 m²/s²
0-3 km storm-relative helicity
204 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.2 K/km

Open this sounding in Storm Lab

Green Bay/Straub, WI (KGRB), 00:00Z

1.8 hours after it, 221 km from the path. August 4, 2017.

Skew-T log-pSkew-T log-p diagram, Green Bay/Straub, WI at 00:00Z on 2017-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 82 joules per kilogram, CIN -52, lifted condensation level 618 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, Green Bay/Straub, WI at 00:00Z on 2017-08-04The 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 42 square meters per square second, 0 to 6 km bulk shear 33 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
82 J/kg
Mixed-layer CIN
-52 J/kg
Surface CAPE
945 J/kg
Mixed-layer LCL
618 m above ground
0-6 km bulk shear
33 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
116 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
5.8 K/km

Open this sounding in Storm Lab

The radar

The NCL Michigan radar (KAPX), 52 km away, was scanning. The volume nearest the touchdown began at 22:11 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
21:00 UTCHEAVY RAIN 1.53 N Maple CityLeelanau, MIRAIN FELL OVER APPROXIMATELY 1.5 HOUR PERIOD.
22:10 UTCTORNADO1 Wsw KewadinAntrim, MIEF0 TORNADO NEAR WILLIAMS DRIVE JUST SOUTH OF BIRCH LAKE. PATH LENGTH OF 0.10 MILES, PATH WIDTH 55 YARDS AND MAXIMUM WIND SPEED OF 80 MPH. DAMAGE TO A FEW HOUSES AND OUTBUILDINGS ALONG AND NEAR WILLIAMS DRIVE, PRIMARILY
22:10 UTCTORNADO3 Nne Elk RapidsAntrim, MIEF0 TORNADO NEAR WILLIAMS DRIVE JUST SOUTH OF BIRCH LAKE. PATH LENGTH OF 0.10 MILES, PATH WIDTH 55 YARDS AND MAXIMUM WIND SPEED OF 80 MPH. DAMAGE TO A FEW HOUSES AND OUTBUILDINGS ALONG AND NEAR WILLIAMS DRIVE, PRIMARILY
22:11 UTCTORNADO1 Sw KewadinAntrim, MIMEDIA RELAYED PICTURES OF LIKELY TORNADO NORTH OF ELK LAKE. TIME AND LOCATION ARE ESTIMATES.
22:15 UTCTSTM WND DMG1 Wsw KewadinAntrim, MIDELAYED REPORT RELAYED FROM ANTRIM COUNTY LAW ENFORCEMENT. TIME ESTIMATED. TREES AND POWER LINES REPORTED DOWN ON WILLIAMS DRIVE.
00:18 UTCHEAVY RAIN 1.232 Nw Rapid CityKalkaska, MIMESONET STATION D5590, 1 WNW RAPID CITY.
00:25 UTCHEAVY RAIN 1.211 Wsw IrontonCharlevoix, MIMESONET STATION D7501, IRONTON.

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 MichiganEvery tornado in Michigan since 1950Warnings in force in Michigan nowThe forecast where you are

The other tornadoes of August 3, 2017

4 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 36:04 PM CDTEF0Cass, MN0.320
August 36:04 PM CDTEF0Cass, MN0.210
August 36:10 PM CDTEF0Cass, MN0.120
August 35:05 PM MSTEF0Maricopa, AZ0.3100

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.