Springtime on the Schuylkill in the 19th century could be extremely hazardous because of sudden ice thaws known as freshets.
Flooding these days on Kelly Drive is often an inconvenience. Traffic gets rerouted and things are back to normal in a few hours. But not long ago, flash floods known as freshets could wreak immense havoc.
Destructive power of freshets
These flash floods occurred in March or April, when ice sheets covering the Schuylkill began to thaw, crack, and move downstream. Occasionally, these floes piled on top of one another, clogging the river at choke points and forming enormous ice dams.