EF1 tornado, Crystal Falls Iron C, Michigan, August 9, 2020

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 9, 2020

Touchdown

9:56 PM CDT (02:56 UTC)

Lifted

9:57 PM CDT (02:57 UTC)

On the ground

1 minutes

Path length

3.8 miles (6.1 km)

Path width

250 yards (229 m)

Deaths

0

Injuries

0

Property damage

$100,000

County

Iron County

Touchdown point

46.024, -88.230

Lift-off point

46.027, -88.151

Record number

2008092056-01

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

• maple about 1 to 2 feet in diameter
• one softwood and one hardwood uprooted facing due west
• multiple breaks approx 6 in to one foot in diameter
• 5 pines snapped about 3 to 4 feet off the ground, each about 8 inches in diameter

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

Increasing moisture and instability ahead of cold front approaching from the Northern Plains aided the development of strong to severe thunderstorms over portions of western Upper Michigan from the afternoon of the 9th into the morning of the 10th.

At least 50 to 100 healthy softwood and hardwood trees were snapped and uprooted on both sides of the road where NWS personnel has access to the path. The tornado, with estimated wind speed of 105 mph, started at Peavy Pond Road and took a path over the northern end of Peavy Pond. Damage could be seen where the tornado moved back onshore and across a small island.

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.

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 Marginal Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 19:55 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 Marquette radar (KMQT), 75 km away, was scanning. The volume nearest the touchdown began at 02:56 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 2020 tornado in MichiganEvery tornado in Michigan since 1950Warnings in force in Michigan nowThe forecast where you are

12 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.