PENNSYLVANIA (WHTM) — The April 25-28, 2011 tornado outbreak, also known as the 2011 Super Outbreak, was a large multi-day event that produced more than 350 tornadoes in 15 states, including Pennsylvania. It is currently the largest tornado outbreak in the history of the United States.

This outbreak killed 321 people and produced around $12 billion (2021 dollars) in damage. The strongest tornadoes hit the southern United States. The outbreak produced three EF5 tornadoes, which are the strongest tornadoes, in one day. The United States sees only one EF5 tornado a year on average.

Pennsylvania was not spared from tornadoes during the outbreak. Many of these tornadoes were weak but some did cause damage. According to the National Weather Service, a total of six tornadoes were confirmed from the early evening hours of April 27 to the early morning hours of April 28, which was the most significant tornado outbreak in central Pennsylvania since 2005.

A tornado watch was issued around 3 p.m. on April 27, 2011, with the threat of tornadoes continuing into the evening, overnight, and early morning hours of April 28. The storms exited the region by mid-morning on April 28.

Below is a list of the tornadoes that struck the state during the biggest tornado outbreak on record.

All storm reports were sourced from the National Weather Service (NWS) or the National Oceanic and Atmospheric Administration (NOAA).

April 27

Potter County EF0 Tornado

This brief tornado spun across southwest Potter County during the evening hours of April 27. The damage caused by the tornado was minimal, with field surveys only finding a few trees down along a two-mile path. Because of the lack of damage, surveyors believe the tornado touched down briefly in several locations with sporadic tree damage.

The damage that was observed was consistent with maximum winds of 65 miles per hour, which puts this tornado at the low end of the EF0 rating category.

April 28

Huntingdon County EF1 Tornado

This tornado occurred in the very early morning hours of April 28, between 2:20 a.m. and 2:25 a.m. It produced damage in Broad Top City and then skipped eastward producing damage.

The tornado uprooted numerous pine trees and caused minor damage to two homes, along the three to four-mile path, and was around 50 yards wide, according to the storm survey. Damage indicators observed during the survey determined the tornado had a maximum wind speed of 85 to 90 miles per hour, which put the tornado at the low end of the EF1 rating category.

Juniata County EF1 Tornado

This tornado occurred between 2:53 a.m. and 3 am. and first produced damage on the east side of East Waterford and then moved northeast, causing sporadic damage on a well-defined path from Honey Grove to Seven Pines in Spruce Hill Township.

The heaviest damage occurred at a farm in Honey Grove where a farmhouse roof, several barns, and farm shed were destroyed. The path of this tornado was over eight miles long and had a width of 100 yards across.

The NWS states the tornado had winds in excess of 110 miles per hour, making it a high-end EF1 tornado.

York County EF2 Tornado

This tornado occurred between 5:55 a.m. and 6 a.m. and touched down near Roundtop Ski Resort. The tornado touched down on the slopes near the main ski lift, traveled down the slope, and destroyed one outbuilding, according to the storm survey.

It then knocked numerous trees as it crossed Roundtop Road and moved up the west side of Pinetown Road. The strongest winds were found to be at the top of Pinetown Hill, where a high-voltage transmission tower was twisted and collapsed. The tornado continued down Pinetown Hill, snapping more trees.

Near the end of the path, one tree fell onto a house along Moores Mountain Road, which destroyed a portion of the house. The wind speed of this tornado was around 130 miles per hour, which makes this tornado a high-end EF2 tornado, and the strongest tornado seen in Pennsylvania during the outbreak.

Lebanon County EF1 Tornado

The National Weather Service states that the tornado began near Palmyra. It first produced damage just west of South Lingle Avenue near West Pajabon Drive and traveled along a two-mile path northeast of the Palmyra Shopping Center along US 422. The tornado was responsible for collapsing the top floor of a house on East Main Street, as well as causing significant damage to a car dealership, which was noted in the storm survey.

Most of the damage that was surveyed was associated with 75 to 90-mile-per-hour winds, making this a low-end EF1 tornado.

Lebanon County EF2 Tornado

This tornado occurred near Ono in Lebanon County and occurred between 6:30 a.m. and 6:33 a.m. It first caused damage near the intersection of Reeds Creek Road and Jonestown Road about half a mile west of Ono. Two farms, a field warehouse, and a few houses sustained significant damage on a knoll just east of Reeds Creek Road.

In addition, a pair of high-tension wire towers were knocked down. No injuries or deaths were reported however a cow sustained injuries. In total, four homes sustained minor to moderate damage, and six farm buildings were destroyed.

Ultimately, the tornado was ranked an EF2 with winds near 115 mph.

On April 27 alone, 122 tornadoes touched down resulting in the deaths of 319 people. According to NOAA, the event was one of the deadlines since formal record-keeping began in 1950.