Formed by cold air sinking down, mammatus clouds are usually seen when there ... including the annual tradition of dyeing the Chicago River green. The roaring wind can be heard, as debris flies ...

Keen photographer Garry Hornby spotted them above Huntington in York and posted: "Stunning mammatus clouds over Huntington road this morning." Fellow club member Kieran Delaney also shared a photo ...

Unusual mammatus clouds were spotted on Wednesday morning in parts of the United Kingdom. The name mammatus comes from the Latin mamma which means 'udder' or 'breast'. The bulging cloud was made ...

Formed by cold air sinking down, mammatus clouds are usually seen when there ... in another successful catch of the rocket booster. Green and fellow Democrats began singing after the House voted ...