Air 4 captured this great photo of some "bumpy" clouds over the Bonney Lake area. What causes these curls?
They are called mammatus clouds and are usually a signal of turbulent, unstable air, and are usually seen after a strong storm has passed.
Their formation is somewhat unique in that they are caused by sinking motion -- typically associated with drying weather as sinking air warms and dries as it does so.
Check the University of Illinois atmospheric sciences site for a more detailed explanation of how mammatus clouds form.
And I invite you to just do a Google Image Search for "mammatus clouds" and marvel at their beauty. They can be a stunning sight to see!