From NWS AWC
Looks more like an olde Japanese woodcut of waves on the ocean, actually… 
Hokusai. 1760 to 1849.
That’s the one!
I’ve seen clouds like that once in my life. By the time I got my camera out they were gone.
Side note: All forty six of Hokusai’s Thirty Six Views of Mount Fuji including The Great Wave are available as large images made from modern facsimile prints at https://en.wikipedia.org/wiki/Thirty-six_Views_of_Mount_Fuji.
They look spectacular printed on matte photo paper.