What does it mean when you see countless cumulonimbus clouds roll in? It usually means that a storm is brewing. When these clouds meet, they collide and tower. This photograph was taken at the Mississippi River on the Illinois side, with the Iowa border showing across.

Stock photo: What does it mean when you see countless cumulonimbus clouds roll in? It usually means that a storm is brewing. When these clouds meet, they collide and tower. This photograph was taken at the Mississippi River on the Illinois side, with the Iowa border showing across. was taken by codydevolder .