Flooding
Flooding is a foreseeable natural disaster in Pennsylvania. It can be difficult to calculate how much rain, or snow melt, will fill how much of an area and how much the water will rise as it spreads to new low-lying areas. One of the easiest ways to make some guesses is based of of the most significant floods on record. There are still many people that were alive during the flooding that occurred in 1972 from Hurricane Agnus. Ask the locals where the water levels got to during that flood. Also, ask about the other floods since then. 2011 had some of the worst flooding since 1972. Some areas were as bad as what they got in 1972, but not all. I don't know why people consistently build, and rebuild, in areas that frequently flood. If you just don't do that you're off to a great start on not having a flood be a problem for yourself. And secondarily, you don't make a problem for others to have to help you in a preventable rescue or recovery. Not building in a flood prone area is also good for your finances, the environment, and your resilience or continuity of operation.
Links
Pennsylvania's Historic Floods Map by Millersville University
Worst floods in Pennsylvania history ABC Channel 27 News, Harrisburg
Floods in Pennsylvania through the years, from Johnstown to Agnes Pennlive
Harrisburg area bids farewell to 2011, its wettest year in history Pennlive
Hurricane Irene tore through central Pennsylvania a year ago this week Pennlive
Will a catastrophic flood hit central Pa? It’s only a matter of time, experts say Pennlive