Roanoke Tidal Wave Cloud vs. Past Crazy Cloud Blogs

I was impressed by the range of neat photos taken of the Shelf Cloud that moved over Richmond, Va., last week. The photos are indeed incredible but are nothing I haven't seen before -- in fact I have blogged about several of the formations shown there.

First up are what I have termed shelf cloud "tendrils." I blogged about these with convective snow showers (ocean-effect snow) in the winter and with a thunderstorm shelf cloud in the summer here in Pennsylvania (pictured above). These formations are often short-lived, and I believe they involve extreme moisture or a sudden change in temperature. An incredible photo of tendrils sighted in last week's storm is shown in our story; you can also see them at the end of this YouTube video.

The second set of bizarre clouds are "tornado dopplergangers" which I blogged about this spring. These benign clouds may, in fact, be large "tendrils" seen from the opposite direction after the shelf cloud has moved over you. These clouds are probably responsible for many false tornado reports. The key is that they are not rotating (a funnel cloud that close would be rotating rapidly). Notice how much the clouds in the YouTube video last week resemble the ones I captured on May 29 (shown above).

And last but not least, check out the "vertical clouds" which appear about halfway down our story. This is something I've blogged about many times... a trick of perspective makes the edge of a curved shelf cloud look like it's vertical (see photo above and illustration below).