EF1 tornado, Grafton to South Rockwood, Michigan, August 24, 2023

1. EF065 to 85 mph

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

2. EF186 to 110 mphthis tornado

   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

EF1

Date

August 24, 2023

Touchdown

10:38 PM EDT (02:38 UTC)

Lifted

10:43 PM EDT (02:43 UTC)

On the ground

5 minutes

Path length

4.9 miles (7.9 km)

Path width

200 yards (183 m)

Deaths

0

Injuries

0

Property damage

$1.0 million

County

Monroe County

Touchdown point

42.009, -83.364

Lift-off point

41.977, -83.278

Record number

2308242038-01

38 damage points were recorded along this path by NWS DTX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 105 mph.

• Many pines uprooted with large main tree limbs down.
• Shingles lifted off house roof (not entire roof)
• Start point. Small branches broken with large amount of leaf litter
• Sub between Reene Dr and Harbor Pointe Ct had multiple trees uprooted and large limbs broken.

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

Thunderstorms producing torrential rainfall led to flooding in the Detroit metro area early Thursday morning (August 24th). Western Wayne county into Monroe county was hardest hit resulting in widespread residential flooding, road closures, and stranded vehicles. Most notable was the closure of Dingell Drive at Detroit Metro Airport which cut off access to the McNamara terminal for several hours. A lengthy closure of I-94 at I-275 was also reported. Numerous rainfall totals in the 3 to 5 inch range were reported mostly in the 6 hour period from midnight to 6 AM. The highest total was 7.36 inches from a CoCoRaHS station in Belleville, a 24 hour total nearly all of which fell during this event.||A second round of rapidly developing thunderstorms began to pop up over Central and Southwest Lower Michigan by the early evening hours of August 24th, with the exceptional moisture and instability in place over southern Lower Michigan. The storms quickly grew upscale and became severe, leading to a west-east line of severe thunderstorms which dropped south through southeast Michigan during the evening hours.||Strong winds in the mid levels allowed for damaging winds to be the primary hazard, with areas of southeast Michigan seeing 60-80 MPH wind gusts which lead to extensive tree damage and power outages, along with some structural damage to homes. At the peak, close to 500,000 customers lost power in southern lower Michigan. A surface low tracking through southern Lower Michigan was able to help spawn tornadoes, with an EF-2 developing over northeast Ingham. This tornado weakened and tracked into Livingston county near Fowlerville before dissipating. This 12 mile track tornado was by far the strongest and longest duration one of the day, and also resulted in 1 fatality as cars were flipped on I-69 in Ingham county. Short lived-weak QLCS tornadoes spun up over Wayne and northeast Monroe counties as the intense thunderstorm complex exited the state around Midnight. Winds with these tornadoes reached 80-105 mph, but even a few wet micro-burst/straight line winds produced wind gusts to 90 mph embedded in the line of storms.||Rainfall rates were intense (1-2��� per hr), but due to the rapid movement of the complex/storms (45-60 MPH), rainfall amounts stayed under 3 inches just about everywhere. Highest rainfall amounts of 1.5-3 inches occurred along the M-59 corridor up to I-69 corridor. Due to heavy rainfall from the previous day (1-3 inches with isolated 5-7 inch totals in Wayne/Monroe counties), even locations which received amounts under 1.5 inches experienced some flooding, mostly low lying/flood prone locations. The Lower River Rouge in Wayne county experienced major flooding and Clinton River in Macomb experienced moderate flooding.||Finally, prolific lightning was observed with the thunderstorm complex as it moved through southeast Michigan, producing thousands of cloud to ground strikes, with a good percentage of them being the stronger positive charged ones.

The weak tornado touched down in a farm field in Ash Township north of Newport Road and half a mile west of North Telegraph Road. The tornado tracked southeast and hit Frenchtown Villa Mobile Home Park where the bulk of the damage occurred on the north side of the park. Roofs were torn off and a manufactured home was flipped over. Other damage included shingle and roof damage on the northeast side of the park. Maximum winds were estimated to be 100 mph. The tornado continued to track southeast and crossed over I-75 by the Meijer Distribution Center where large tree limbs were downed to the east of the center. As the tornado continued southeast, several large tree limbs were downed with leaning power poles noted. The tornado dissipated in a farm field about half a mile east of North Dixie Highway and south of Post Road in Frenchtown Township in Monroe County.

The weak tornado touched down on Carleton Rockwood Road, one mile east of Telegraph Road. The tornado tracked eastward across Armstrong Road where there were numerous large tree limbs down. There were multiple trees that were snapped and tops taken off, along with some house shingles partially torn off near Brandon Road. The tornado continued to track east across I-75 and South Huron River Drive into where numerous large tree limbs were blown down, one of which fell on a house. There was also a roof partially torn off and garage door damaged near South Huron River Drive and North Dixie Highway. Maximum winds were estimated to be 105 mph. The tornado then crossed into Wayne County and moved over the Lake Erie Metropark Golf Course with multiple large tree limbs downed before ending at the Detroit River. The total path length of the tornado as it moved through Monroe and Wayne counties was 5.4 miles.

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 severe thunderstorm watch, issued at 22:37 UTC and running to 03:20 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 Enhanced Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:59 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.

The Detroit radar (KDTX), 80 km away, was scanning. The volume nearest the touchdown began at 02:36 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 2023 tornado in MichiganEvery tornado in Michigan since 1950Warnings in force in Michigan nowThe forecast where you are

21 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.