Roberta wrote, “I saw these interesting clouds off the Bluff Trail near Salal Beach [on The Sea Ranch]. I just found out from a fascinating TED talk by Gavin Pretor-Pinney that they’re Kelvin-Helmholtz clouds.”
Kelvin-Helmholtz clouds are also called billow clouds. Park Aide Roberta saw some from the Salal Trail on The Sea Ranch.
Roberta learned more about these clouds from a TED talk by Gavin Pretor-Pinney. Here's the link to that talk: http://www.ted.com/talks/gavin_pretor_pinney_cloudy_with_a_chance_of_joy.html
I sent this photo to Ken Holmes and he wrote, "It is produced as the speaker, Gavin Pretor-Pinney, explains by wind shear (or varying speed) that flows within and above these stable-type clouds."
Thanks to Roberta for allowing me to share her photo with you here. Cloud watching is a Coast tradition!