<p>Christopher, there seems to be a wider variety of "options" around than compared to mammatus clouds, also uncommon. but i seems they can occur in a wide variety of geographic areas. maybe the key thing is that (like other uncommon cloud formations like mammatus) they are not only uncommon, but fairly transient phenomena, so not only do you have to be lucky to see them, you have to also be lucky and have your camera...<br>
here are a couple of links to web info.</p>
<p>https://en.wikipedia.org/wiki/Wave_cloud</p>
<p>https://www.washingtonpost.com/news/capital-weather-gang/wp/2015/03/30/amazing-undulatus-asperatus-wave-clouds-seen-in-georgia-south-carolina-photos/<br>
https://www.washingtonpost.com/news/capital-weather-gang/wp/2015/12/16/pic-of-the-week-remarkable-wave-clouds-paint-the-sky-over-Utah/</p>
<p> </p><div></div>