Tornadoes · United States · Michigan · 2011

EF0 tornado, Alabaster Jct, Michigan, August 7, 2011

This EF0 tornado ran 0.2 miles across Iosco County on August 7, 2011, touching down at 4:50 PM EDT and reaching 50 yards wide. It killed nobody, and did $75,000 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 7, 2011
Touchdown
4:50 PM EDT (20:50 UTC)
Lifted
4:51 PM EDT (20:51 UTC)
On the ground
1 minutes
Path length
0.2 miles (0.3 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$75,000
County
Iosco County
Touchdown point
44.235, -83.548
Lift-off point
44.236, -83.545
Record number
1108071450-01

What the Weather Service recorded

Scattered showers and a few thunderstorms moved across Northern Lower Michigan. One storm produced a tornado just before moving out over Tawas Bay.

Several people witnessed the tornado touch down between US-23 and Tawas Bay. The tornado was on the ground for less than a quarter-mile, crossing Douglas Drive just north of Lakeview Drive, before reaching the bay as a waterspout. Forty trees were downed, and six homes suffered damage, mostly roof damage due to those falling trees. Winds were estimated at 70 mph.

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.

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 20:01 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.

Alpena, MI (KAPX), 12:00Z

8.8 hours before the tornado, 130 km from the path. August 7, 2011.

Skew-T log-pSkew-T log-p diagram, Alpena, MI at 12:00Z on 2011-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2 joules per kilogram, CIN -93, lifted condensation level 761 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, Alpena, MI at 12:00Z on 2011-08-07The 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 40 square meters per square second, 0 to 6 km bulk shear 28 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
2 J/kg
Mixed-layer CIN
-93 J/kg
Surface CAPE
495 J/kg
Mixed-layer LCL
761 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

Alpena, MI (KAPX), 00:00Z

3.2 hours after it, 130 km from the path. August 8, 2011.

Skew-T log-pSkew-T log-p diagram, Alpena, MI at 00:00Z on 2011-08-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 214 joules per kilogram, CIN -9, lifted condensation level 605 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, Alpena, MI at 00:00Z on 2011-08-08The 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 -21 square meters per square second, 0 to 6 km bulk shear 25 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
214 J/kg
Mixed-layer CIN
-9 J/kg
Surface CAPE
848 J/kg
Mixed-layer LCL
605 m above ground
0-6 km bulk shear
25 kt
0-1 km bulk shear
4 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
20 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.3
0-3 km lapse rate
6.2 K/km

Open this sounding in Storm Lab

The radar

The NCL Michigan radar (KAPX), 119 km away, was scanning. The volume nearest the touchdown began at 20:49 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
20:10 UTCTSTM WND GST 403 Wnw PigeonHuron, MI
20:10 UTCHEAVY RAIN 13 Wnw PigeonHuron, MI0.5 HOUR TOTAL
20:49 UTCTSTM WND DMGTawas CityIosco, MIPOWER LINES DOWN ACROSS US 23...TOWNLINE ROAD...AND BAY DRIVE. ONE TREE WAS UPROOTED AND AFFECTED A GAS LINE. TIME ESTIMATED FROM RADAR.
20:50 UTCTSTM WND DMGTawas CityIosco, MITREE DOWN AT TOWNLINE ROAD AND BAY DRIVE.
20:50 UTCMARINE TSTM WIND 40Tawas CityIosco, MIGUST REPORTED WITH SHELF CLOUD
20:50 UTCTORNADO 0Tawas CityIosco, MINWS STORM SURVEY REVEALED BRIEF TOUCHDOWN OF A TORNADO EAST OF US-23 ON DOUGLAS RD. NEAR LAKEVIEW RD. APPROXIMATELY 40 TREES WERE DOWNED AND SIX HOUSES DAMAGED. WINDS ESTIMATED AT 70 MPH. APPROXIMATE PATH LENGTH WAS 0.20
21:00 UTCTSTM WND DMGTawas CityIosco, MIOAK TREE DOWN ON A HOUSE AT 9TH ST AND HARRIS AVE. TIME ESTIMATED FROM RADAR.

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

The other tornadoes of August 7, 2011

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 712:35 PM CDTEF0, PR0.880$80,000

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.