Here is something special and very rare.
On Friday evening (March 11, 2016), a few minutes before sunset, a thin band of Kelvin Helmholtz clouds developed above a cumulonimbus anvil and became iridescent for just three minutes before dispersing.
The first three photographs on this page, in which the iridescence is bright, were taken with a Panasonic Lumix DMC-TZ60 in intelligent auto mode and x60 zoom magnification.
The distant view – at the bottom of the page – was taken a short while before. The Kelvin Helmholtz cloud band had not yet become colorful.
To see Kelvin-Helmholtz clouds is rare, for them to become iridescent is much rarer and for a swallow to fly past during the fraction of a second when a photograph is taken defies all odds and is almost miraculous!
Read more about Kelvin Helmholtz clouds, and see more photos
Read more about cloud iridescence

Iridescent Kelvin-Helmholtz clouds with passing swallow, Mutare, Zimbabwe Photo taken March 11, 2016 by Peter Lowenstein.

Dispersing iridescent Kelvin-Helmholtz clouds, Mutare, Zimbabwe, March 11, 2016. Photo by Peter Lowenstein.

Distant view of Kelvin-Helmholtz cloud band, Mutare, Zimbabwe, March 11, 2016. Photo by Peter Lowenstein.
Bottom line: Iridescent Kelvin Helmholtz clouds – clouds that look like ocean waves – on March 11, 2016 over Mutare, Zimbabwe.