. Lenticular means "lens shaped". They normally align at right-angles to the direction of the wind. As a note of interest, sailplane pilots look for these types of clouds because they indicate a long series of standing wind waves. These kinds of winds can take a glider to great altitudes and for long distances. I have a friend, Cecil Craig, who flew a glider 268 miles in 1967 from Mt. Rainier in Washington to Crater Lake in Oregon by following a series of these winds over the Cascade mountain range. He broke a few world records with that flight! This photo was taken in Colorado at Keystone Ski Resort, Breckenridge Resort can be seen far in the distance.
Mt. Rainier looked "angelic" with a halo-like cap cloud, but these clouds are anything but heavenly; they are formed by strong upper level winds, making for some dangerous conditions for climbers. These clouds usually indicate a change in the next day's weather. Sure enough, we did not see the mountain the following day, it was socked in by low clouds. Many high mountains "make their own weather". We heard that the mountain is visible only 80 days out of the year, so we were happy we had an unobstructed view the day before this photo was taken. I was excited to see it look like this too!
This is a very simplified diagram of how a rainbow forms. Raindrops work like tiny prisms refracting the white light from the sun. Rainbows are seen when a storm passes and the sun shines through the raindrops. They can be seen only when the sun is behind the observer.
