Certified GKH Gardening Expert
I am unable to tell from the description. If you could send a picture, then that would help me greatly. From your description, it sounds like a certain wasp nest, called a dirt dauber. Have care in dealing with these. Even though they are not known for being aggressive, they still have stingers. A picture will help me identify this correctly.
When I break the dirt tube it has yellow powder inside. What is this from.