Well I found out that cowagooba is actually kawagoopa.

Cowabunga pedia

The word evolved from “kawabonga,” a word used by the character Chief Thunderthud on the United States children’s television program Howdy Doody in the 1950s. “Kawagoopa” was an all-purpose exclamation of the Tinka Tonka Indians, the fictitious tribe of Princess Summerfall Winterspring and Chief Featherman, and “kawabonga” was the equivalent exclamation of Chief Thunderthud, who was of the Ooragnak Tribe. By the 1960s, surfers who had grown up watching Howdy Doody adopted it for surfing use, turning it to “cowabunga.”

What’s Cowagooba!? 18 Sep 2007