SPC Stats

Path length: 5.5 miles

Width:  600 yards

Fatalities:  0

Injuries:  0

Rating:  F1

County:  McKean

Tornado Path

SPC Coordinates: 41.77/-78.62 Start and End listed as the same 

Corrected Coordinates from NWS State College Database:

Start: 41.75 / -78.61, End: 41.87 / -78.43

Coordinates of the two tornadoes if you break it down into two tornadoes:

 Kinzua Bridge: Start: 41.75536, -78.60607, End: 41.77502, -78.54727

Farmers Valley: Start: 41.83108, -78.45747, End: 41.8734, -78.44306

    Note:  Exact tornado path may not be straight and/or continuous.

On July 21, 2003, a derecho moved across portions of Ohio, Pennsylvania, New York and New England. Per the Storm Prediction Center, it spawned 20 tornadoes. The focus of this summary is on one of the most notable tornadoes of this outbreak. It hit the Kinzua Bridge in McKean County, PA. Check out our summary on the strongest tornado of this outbreak: An F3 that hit Ellisburg, PA.

The derecho was unusual as it formed an “eye-like” feature. It looked like a hurricane as it moved across Pennsylvania. It is possible (likely) that the Kinzua Bridge tornado event was made up of two separate tornadoes; one that hit the bridge, and a second near Farmer’s Valley. We will delve into this more below.

The Kinzua Bridge Viaduct was built in 1882. At 301 feet tall and 2053 feet long, it was at one time the largest railroad viaduct in the world. At the time of the collapse, it was the fourth largest in the United States. The bridge was once capable of holding the 511-ton “Big Boy”, the largest steam engine in the world. In June 2002, it was closed to rail traffic after an inspection by the Department of Conservation and National Resources (DCNR) showed significant structural weakening, and in August 2002, it was closed to pedestrian traffic. At the time the tornado struck, the bridge was amid a $10.8 million restoration project that began in February 2003.

Photo of the Kinzua Bridge Viaduct, taken in 1971, via Wikipedia.
An aerial view of the devastated park via Kinzua Bridge State Park.

The tornado was embedded within a large swath of downburst winds. It developed about a mile west of the Kinzua Viaduct in a wooded area. It moved east-northeast through Kinzua Gorge, following the Kinzua Creek, downing many trees. The tornado struck the Kinzua Viaduct Bridge in the Kinzua Bridge State Park. 9 out of the 20 bridge supporters were destroyed leading to the collapse of the structure.

A couple of studies were conducted to find out why the bridge collapsed. The investigations determined that towers 10 and 11 collapsed first. Next, towers 12 through 14 were picked up off their foundations, moved slightly to the northwest, and set back down intact, only being held together by the railroad tracks. Following this, towers four through nine collapsed toward the west. Finally, as the tornado continued moving east-northeast, towers 12 through 14 collapsed toward the north-northeast, leaving a clear cyclonic pattern to the collapsed trusses. The investigation found that the bolts holding the bases of the towers to the anchor blocks were rusted. The engineering studies determined that 94 mph winds brought down the bridge. The tornado applied an estimated 90-short-tons of lateral force against the bridge. They also hypothesized that the whole structure oscillated laterally four to five times before fatigue started to cause the bolts to fail. In less than 30 seconds, the 121-year-old bridge was destroyed.

The tornado continued for another 2.5-miles through the gorge downing many trees before it lifted. Over 1,000 trees were snapped off or uprooted in the Kinzua Gorge and Kinzua Bridge State Park from this tornado. Peak wind speeds reached 100 mph. One employee of Kinzua Bridge State Park was injured during the collapse of the bridge.

At this point, things get a bit murky. The NCDC/NWS State College suggests the same tornado lifted and then developed again 2 miles north of Smethport. It is this author’s opinion that a separate tornado formed.

Only downburst damage was observed until a point approximately two miles north of Smethport. It was here that tornado damage was discovered. The tornado moved north-northeast through the small town of Farmer’s Valley. Along this 3-mile path, many trees were downed. A barn was destroyed and two others were damaged. Two homes and a church were also damaged. Wind speeds in this damage segment were estimated to be between 80-90 mph.

There was a nearly 6.5-mile gap between tornado damage. This a rather long gap for a “skipping tornado” which is why it is my opinion that we had two separate tornadoes in McKean County.

It would have cost an estimated $45 million to rebuild the bridge. The state decided to not rebuild it. It was decided to leave the collapse trusses where they are for people to view the forces of nature and a hiking trail was created in this area where people can walk up to the wreckage. In 2011 the Kinzua Sky Walk opened, allowing people to walk out over the undamaged part of the bridge. Kinzua Bridge State Park is listed by the DCNR as one of the top 20 must-see state parks in the State of Pennsylvania.

A view of the Kinzua Bridge Skywalk taken on August 13, 2022. Image taken by the author.
Looking northeast from the Kinzua Bridge Skywalk on August 13, 2022, showing a hill where trees have not regrown after being flattened by the twister. Photo via the author.
The wreckage of the bridge, on August 13, 2022. Photo taken via the Author.
The wreckage of the bridge, on August 13, 2022. Photo taken by the author.
The wreckage of the bridge on August 13, 2022. Photo taken by the author.
The twisted mass of the towers on August 12, 2022. The Skywalk is visible toward the middle top of the image. Photo taken by the author.
A close-up of some of the twisted metal on August 13, 2022. Photo taken by the author.
Close up of the twisted metal on August 13, 2022. Photo taken by the author.
Another view of the twisted wreckage on August 13, 2022. Photo taken by the author.
Another view of the twisted remains on August 13, 2022. Photo taken by the author.
One of the rusted anchor bolts that failed. Photo taken by the author.
A view of the collapsed trusses on August 13, 2022. Photo taken by the author.


Radar of the derecho as it moved crossed North-Central Pennsylvania, producing the Kinzua Bridge and Ellisburg tornadoes. Note the eye-like feature it formed.

Photos from NWS State College

The collapsed Kinzua Bridge Viaduct.
Blowdown in Kinzua Bridge State Park.
The collapsed bridge and snapped trees adjacent to the bridge.
Trees blown down near the bridge.
Snapped trees at a picnic area in Kinzua Bridge State Park.
A clearly convergent tree-fall pattern near the bridge.
Damage to the Grace Chapel in Farmer's Valley.
Snapped telephone pole and tree down on a house in Farmer's Valley.
Convergent pattern in the grass.
The barn that was destroyed in Farmer's Valley.

Newspaper Clippings

Tornado Talk Trip to Kinzua Bridge

On Saturday, August 13, 2022, the author of this summary, Nick Wilkes, and the owner of Tornado Talk, Jen Narramore, visited the park. We toured the visitors center and walked out over the Skywalk. After taking in the breathtaking views from the Skywalk, we hiked down the side of the hill to the bottom of Kinzua Gorge and walked up to the wreckage. It was impressive to see the twisted remains of the trusses lying there. The tornado was rated F1 with maximum winds of 100 mph, and engineering studies showed that the winds that brought the bridge down was about 94 mph. This goes to show that “weak tornadoes” really are not “weak.” The photos below show the various signs and plaques across the park and visitor’s center. 

Nick and Jen on the Skywalk.
A newspaper clipping that is on display in the visitor's center.
Some photos of the bridge before the tornado destroyed it that are on display.
Photos showing the history of the bridge.
There are quite a few Big Foot sightings in the vicinity of Kinzua Bridge State Park 🤔.
The fallen trees and trusses became a safe haven for the local wildlife.
A neat postcard that is sold at the gift shop.
After visiting the park, we stopped by the Kane Historical Society to get information on the F4 tornado that struck the town on May 31, 1985. The historical society is selling blocks of wood from the original bridge; this one has a knife that was made from a railroad tie.


We gathered information for this event from the SPC/NCDC Databases, and the National Weather Service State College Tornado Database, and found the following differences:

Path Length:

  • SPC/NCDC have a 5.5-mile path.
  • NWS State College has a 12-mile path. 


      • SPC/NCDC list 0 injuries.
      • NWS State College has 1 injury.  

      Questions or comments about this summary?  Contact us here!

      Join the tornado history discussion on our Discord Server!

      Note:  There are some images/videos in our summaries that were licensed to us to be used only on this website. If you would like to use an image/video in your project or blog, please contact us and we will grant permission if possible.

      Newspaper clips are embedded via newspapers.com. Please see their terms and conditions.


      Would you like to see more summaries like this one?  Support Tornado Talk on Patreon! Become a Patron!


      Leave a Reply

      Avatar placeholder
      You cannot copy content of this page