Thunderhead 1 : A popular term for a cumulonimbus cloud (CB) formation associated with a thunderstorm. It is characterized by a large vertical column topped by a mushroom or anvil-shaped head
The Canadian Interagency Forest Fire Centre (CIFFC), Glossary of Forest Fire Management Terms, Manitoba, Canada 2003. http://bcwildfire.ca/mediaroom/Backgrounders/2003_ Fire_Glossary.pdf, (For Fr - Canad) {474}