What's the meaning of RIP CURL?

Perhaps "A 'rip' is a very dangerous area in the sea: a current which runs parallel to the beach. If you swim there you can get sucked under the water and dragged out to sea. 'Curl' refers to the waves you see at a rip that warn you not to swim there. Australians are taught to look for a V shape in the water which could be a rip, and to avoid it! On our popular beaches, there is always a lifeguard who watches the beach very carefully, and two flags. If you always swim between the flags, you know that that water is safe."
 Someone also says
Rip curl: large curling wave: n.a large and powerful wave with a curling crest that is particularly good for surfers to ride on.
And in Spanish, ¿Ola peligrosa? WTF