Cumulonimbus 5 : The ultimate growth of a cumulus cloud into an anvil-shaped cloud with considerable vertical development, usually with fibrous ice crystal tops, and usually accompanied by lightning, thunder, hail, and strong winds
National Wildfire Coordinating Group (NWCG), Glossary of Wildland Fire Terminology, NWCG Program Management Unit, National Interagency Fire Center, Boise, ID, USA 2014. http://www.nwcg.gov/pms/pubs/glossary/pms205.pdf, (For Fr - Amer) {45}