Below 2 Km or below 6,000 Feet
Stratus Clouds - In the winter of 1803 a London pharmacist named Luke Howard derived a cloud classification system based on four cloud types.
Flat or "layered" (stratus)
Puffed or "heaped" (cumulus)
Wispy or "curled" (cirrus)
His system won quick acceptance.
There are three primary cloud forms, (1) the heap cloud, known as Cumulus, (2) the layer cloud, known as Stratus, (3) the streak cloud known as Cirrus.
The three basic cloud forms are then subdivided into ten different divisions based on cloud base height. They are from the highest to lowest
1. Cirrus, 2. Cirrostratus 3. Cirrocumulus 4. Altostratus 5. Altocumulus 6.
Stratus 7. Stratocumulus 8. Nimbostratus 9. Cumulus 10. Cumulonimbus.
The World Meteorological Organization recognizes 10 genera, 20 species and 30 -odd varieties of cloud names.