Despite the existence instruments created to predict the weather, sometimes, Mother Nature throws a curveball.

What was forecasted as a Category 1 hurricane, an F1 tornado, a minor flood, a small fire, or a light dusting of snow, can turn into an extremely unpredictable weather pattern without warning.

While there are systems in place to help people in the path of destruction prepare for devastating weather events (like evacuations ahead of a hurricane), that wasn't always the case. To this day, ruinous weather patterns can move in with little to no notice and all Pennsylvanians can do is hope for the best and brace for the worst.

According to a list compiled by LoveExploring, the "most shocking" weather event to ever occur in Pennsylvania was the Johnstown Flood of 1889. This devastating storm killed 2,209 people and is known as the most catastrophic weather event in Pennsylvania history.

Here's what LoveExploring detailed about the state's worst weather event of all time:

"The death toll alone – with 2,209 people killed – makes the Johnstown flood of May 31, 1889, one of the biggest natural disasters across the US. The flood was caused when the South Fork Dam failed due to torrential rainfall, causing around three billion gallons of water to flow in Johnstown's direction. Buildings were crushed, nearly 100 entire families were wiped out, and more than 750 victims were never identified. They’re buried in a dedicated Plot of the Unknown in the town’s Grandview Cemetery."

For a continued list of the most shocking weather events to occur in each state, visit loveexploring.com.