text: A rip current , commonly miscalled a rip tide , is a strong channel of water flowing seaward from near the shore , typically through the surf line .
simplified: A rip current is a strong surface flow of water returning seaward from near the shore ( not to be confused with an undertow ) . It is often mistakenly called a `` rip tide '' or `` riptide '' , though the occurrence is not related to the tides .