My photo of a Cumulonimbus Cloud

[Bretrick]

 

[seadoug]

Beautiful!

 

[JustDave]

 

[KSav]

"Towering cu," as my ex (an atmospheric scientist) would call those. A sure sign of instability in the atmosphere.

 

[OneEyedDiva]

I love seeing those big, puffy clouds. This was taken in Bermuda, probably from the cruise ship. But it's not as spectacular as the clouds you and @JustDave caught Bretrick.