Flash rip currents are temporary rips generated by increased volumes of water brought to shore from concentrated sets of waves, especially when the surf is heavy. Traveling rip currents are similar to flash rip currents, but traveling rips have a predictable movement. These rips do not accompany depressions in sand or reef formation. They move along the beach pushed by the prevailing direction of the waves. A rip may seem especially rough or choppy, may have the dark color of deeper water, and it may or may not have foam.
Rips pick up kelp, debris, sand, giving water a dirty or muddy quality.
Rips pull hardest when there is a lull in a set. Seasonally, rips pull the most in the spring and early summer in San Diego. There are three major components to a rip current. The feeder is the main source of supply for the rip. Water that is pushed up on the beach and pull back by gravity seeks a path of least resistance, like a channel.