2.  Stratus
 Stratocumulus
 Nimbostratus

3. Stratus
A low grey
cloud that
has a flat
base.

4. Stratocumulus
Large dark,
rounded
masses,
usually in
groups, lines,
or waves

5. Nimbostratus
Formless
cloud layer
that is
almost
uniformly
dark grey.

6.  Altocumulus
 Altostratus

7. Altocumulus
Grey, puffy
masses,
sometimes
rolled out in
parallel
waves or
bands.

8. Altostratus
Grey or
blue-grey
clouds that
usually cover
the entire
sky.

9.  Cirrus
 Cirrocumulus
 Cirrostratus

10. Cirrus
Thin and
whispy
clouds.

11. Cirrocumulus
A patch or
layer of
cloud
consisting of
tiny
individual
cloudlets.

12. Cirrostratus
Sheet-like
and nearly
transparent.

13.  Cumulus
 Cumulonimbus

14. Cumulus
Noticeable
vertical
development
and clearly
defined
edges.

15. Cumulonimbus
Towering
vertical cloud
that is very
tall, dense, and
involved in
thunderstorms
and other
inclement
weather.

16.  Fog
 Mammatus
 Lenticular
 Contrails

17. Fog
Suspended in
the air at or
near the
Earth's
surface.

18. Mammatus
Cellular
pattern of
pouches
hanging
underneath
the base of a
cloud.

19. Lenticular
Stationary
lens-shaped
clouds

20. Contrails
Artificial
clouds that
are the
visible trails
of condensed
water vapour
made by the
exhaust of
aircraft
engines.