Emily L. Ferguson (Sunset cloud column) - I am mystified by your comment 'I actually was so low on the beach in front of that fringe of grass that the cloud seemed to be vertical.' Are you saying the cloud was really not vertical but horizontal? Does that mean the grass was actually growing horizontally? Either way, its an interesting phenomena.
The cloud was probably high up in the sky and "horizontal" but maybe it was originally a contrail. I was on the opposite side of the sunset, the east side, and the beach was about 20 feet below the fringe of dune grass. Hard to explain but it was neat that it appears, as Mr. Stempel mentioned, something like Old Faithful might appear - to be erupting out of the earth.
HTH -- Emily L. Ferguson elf@cape.com 508-563-6822 New England landscapes, wooden boats and races, press photography Beetle cats on the web at: http://www.vsu.cape.com/~elf http://www.beetlecat.org/store.html#yrbook