These types of clouds are created from air in the atmosphere coming across an obstacle (like a mountain or cold front). These disturbances cause the air to rise and move in this pattern.

In the image, Vesuvius' caldera — a large bowl-like depression caused by the collapse of the mountain's summit ... the gap in the otherwise thick clouds covering Vesuvius and Naples.

It's a good idea to throw on warm layers, grab your sunglasses and get your ice scraper handy as you get ready to head out ...

Mammatus clouds cover the sky over the Ernst-Taehlmann-Park ... When air blows into a mountain, it's forced up and over the landscape, which can generate lenticular clouds. Because of this ...

Scattered snow showers stick around into the afternoon with minor additional accumulations. Roads are slick and snow-covered and will remain that way.

A sea of clouds may cover the area on mornings from late September ... and many early morning visitors who throng a mountain observation deck 1.1 kilometers from the castle can leave disappointed.