Cloud atlas
The ten genera, fifteen species and nine varieties of the WMO International Cloud Atlas, with symbols and abbreviations.
Mother-clouds and special clouds
Suffixes recording where a cloud came from.
- genitus (gen)
- Growth from part of a mother-cloud, which keeps its own identity — e.g. altocumulus cumulogenitus (Ac cugen).
- mutatus (mut)
- Complete transformation of one genus into another, the mother-cloud losing its identity — e.g. stratocumulus stratomutatus (Sc stmut).
- homogenitus (hogen)
- Cloud formed by human activity: aircraft contrails, cooling-tower plumes and industrial cumulus.
- homomutatus (homut)
- Persistent contrails spread and reshaped by upper winds into cirriform sheets over time.
- cataractagenitus (cagen)
- Cloud generated by the spray of a waterfall.
- silvagenitus (sigen)
- Cloud formed over a forest from the moisture it evaporates.
- flammagenitus (flgen)
- Cloud produced by the heat of a wildfire or volcanic eruption — pyrocumulus.