While most clouds have wispy edges, mammatus lobes, usually only stable for a few minutes, form well-established boundaries that result in the dense, rounded shapes seen over Saskatchewan on June 26.

The overshoot resulted in the storm cloud reaching -111°C, becoming the coldest storm cloud temperature ever recorded. The peak of the clouds had risen to an altitude of over 20.5 kilometres ...

The cloud started when a storm pushed a mass of hot air from the Sahara Desert over the Mediterranean Sea. That same storm brought some much-needed rain for Spain’s drought-ridden crops, but ...