EF1 tornado, Cliff Mine, Pennsylvania, May 7, 2024

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

May 7, 2024

Touchdown

1:49 AM EDT (05:49 UTC)

Lifted

1:50 AM EDT (05:50 UTC)

On the ground

1 minutes

Path length

0.2 miles (0.3 km)

Path width

150 yards (137 m)

Deaths

0

Injuries

0

Property damage

$75,000

County

Allegheny County

Touchdown point

40.462, -80.197

Lift-off point

40.461, -80.194

Record number

2405072349-01

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

• Trees leaning SE, approx 15
• Trailer rolled off blocks in parking lot
• Part of roof from outbuilding, looking wsw

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

Potent low pressure tracked across the Upper Midwest from May 7th into May 8th, pushing an occluded boundary across the Upper Ohio Valley. Strong warm and moist advection kept conditions favorable for convection into the overnight hours, with high levels of shear and a surface trough also supporting storm development. Cyclic supercell structures supported a few instances of straight line wind damage, as well as three tornadoes in southwest Pennsylvania. One of these ended up being one of the stronger and more significant tornadoes in the region's recent history, a high-end EF2 that ultimately tracked across 15 miles and three states.

A storm survey performed by the National Weather Service confirmed that a brief EF-1 tornado, with maximum winds of 105 MPH, occurred near Aten Road in Findlay Township, just west of I-376 and adjacent to the Pittsburgh International Airport. |The tornado touched down north of Aten Road, where a trailer on blocks in a parking lot was overturned, with some tree damage nearby. The tornado then progressed southeast, snapping at least 15-20 trees along the northern side of Aten Road. This area represented the strongest damage, where the 105 MPH wind was|assigned. A nearby outbuilding lost a metal roof in several pieces. One portion fell on the interstate, while another blew over the interstate and landed roughly a quarter-mile downwind. The tornado caused additional tree damage near the Edgeworth Security and Marriot hotel buildings. The tornado likely then lifted, as no other appreciable damage was noted other than the previously noted roof pieces that were blown downstream.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

23 minutes of warning. NWS PBZ issued a tornado warning for this county at 05:26 UTC, 23 minutes before the tornado touched down, in force until 06:00 UTC.

The county was under a tornado watch, issued at 05:02 UTC and running to 06:22 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 Marginal Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 01:11 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.

Pittsburgh International (PIT), 5 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Pittsburgh radar (KPBZ), 8 km away, was scanning. The volume nearest the touchdown began at 05:51 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 2024 tornado in PennsylvaniaEvery tornado in Pennsylvania since 1950Warnings in force in Pennsylvania nowThe forecast where you are

52 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.