EF1 tornado, Grayling, Michigan, June 18, 2012

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

June 18, 2012

Touchdown

9:28 PM EDT (01:28 UTC)

Lifted

9:30 PM EDT (01:30 UTC)

On the ground

2 minutes

Path length

1.3 miles (2.1 km)

Path width

350 yards (320 m)

Deaths

0

Injuries

0

Property damage

$60,000

County

Crawford County

Touchdown point

44.586, -84.535

Lift-off point

44.583, -84.510

Record number

1206181928-01

A warm front allowed warm and moist air to surge north into Northern Michigan. Initial thunderstorms developed in Eastern Upper Michigan in the afternoon; some of these produced large hail. Incoming thunderstorms organized into a line as they crossed Northern Lake Michigan; this squall line produced many reports of 40 to 55mph winds, but only a few pockets of wind damage, in addition to a single tornado.

This EF1 tornado impacted the Forest Dunes Golf Club. The initial touchdown was near the entrance to the club. Damage along the first half of the path was sporadic, with some trees uprooted and/or snapped. Damage intensity increased as the tornado reached a clear-cut area adjacent to its path, allowing the winds to more directly strike a large stand of trees. Damage in this one stand, alongside one of the fairways at the club, was considerable, with the majority of the trees felled. All told, over 100 trees were uprooted and/or snapped, including a mix of hardwoods and softwoods. Maximum winds were estimated at 100 mph.

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.

The county was under a severe thunderstorm watch, issued at 21:47 UTC and running to 02:42 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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 00:52 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 NCL Michigan radar (KAPX), 39 km away, was scanning. The volume nearest the touchdown began at 01:29 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 2012 tornado in MichiganEvery tornado in Michigan since 1950Warnings in force in Michigan nowThe forecast where you are

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.