Anu says first used in 1954: Chief Thunderthud. Now there's a
memory, along with Clarabelle, Summerfallwinterspring, Buffalo
Bob and the Peanut Gallery. And of course, Howdy Doody.

I grew up as one of the first in the generation to have children's TV and fondly remember being a member of the peanut gallery, and remember Chief Thundercloud and all the rest, however the association I recall best for the phrase 'cowabunga' is actually the Charles Schultz's Peanuts character Snoopy in his "Surfer Joe" persona where we'd see him, wearing his baggy baggy surf short, hanging ten from his surfboard while on the top of his doghouse as it transformed into an imaginary wave. The Ninja Turtles were relative newcomers and were no doubt paying homage to Surfer Joe Snoopy. Cheers.

WELCOME DOUG I

And thanks for the Snoopy Surfer memory. I had forgotten that
one. TMNT are too new for me, though I am familiar with them
I've never given them much attention.

Cheers back at'cha! Don't be a stranger.

I love this word, though that horrible puppet scared me to death. My main association with cowabunga is the TMNT, having watched them repeatedly with my son.

As I mentioned I am not familiar with TMNT, other than advertisements, but I do remember a trailer with the word
in it.