With storm chasing season now well underway, it’s that time of the year when you may begin noticing some extraordinary cloud structures bubble up in the sky.

Torsten Schön captured this spectacular shot of mammatus clouds at sunset in Paraguay, with more images below captured by our Weather & Radar users.

Mammatus clouds are a type of cloud most common to, but not exclusive to, cumulonimbus rainclouds.

The mammatus name is derived from the latin word “mamma”, which means “udder” or “breast”, owing to its pouch-like appearance hanging down from the base of a cloud.

Their shape and distinction can vary dramatically depending on conditions, and also time of day in regard to sunlight, as you can see from the gallery of images above.

They typically develop in association with thunderstorms, most frequently during the summer months.

The turbulence and downdrafts within the storm clouds creates the uneven cloud base; more intense storms can produce larger and more distinct formations. This contrasts to the usual upward growth of clouds.

People flock to hotspots all over the world to chase tornadoes and catch structures like these, particularly to the likes of the Great Plains in the US.

Whilst they may look ominous and can certainly accompany a risk of heavy rain, lightning, hail and even tornadoes, they are not necessarily a direct sign of impending severe weather and can also form once a storm has passed.

They don’t hang around too long either, perhaps 10 or 15 minutes at a time, so you’ll be lucky to catch these fleeting beauties.

Have you ever snapped a shot of these clouds before? We’d love to see them here.