Identify the type of cloud on the basis of the given characteristics : 1. High, thin, puffy white clouds of ice crystals that look like ripples 2. They appear between 20000 feet and 40000 feet above the Earth's surface 3. One of its types is called a 'mackerel sky' because the clouds resemble large fish scales, especially when they are coloured pink at sunset Select the correct answer.
- (a)Altostratus
- (b)Cirrostratus
- (c)Altocumulus
- (d)Cirrocumulus
Correct — D, Cirrocumulus. All three clues point to the same cloud. The prefix 'cirro' marks a high cloud made of ice crystals, and the height band given in the stem, 20,000 to 40,000 feet, is the high-cloud band; the suffix 'cumulus' marks the puffy, heaped, convective form, which is why the cloud appears as ripples of small white cloudlets rather than as a smooth sheet. And the nickname is decisive: cirrocumulus patches arranged in fine rows are the 'mackerel sky', named because they look like the scales of a fish and are often tinted pink at sunrise and sunset.
- (a)Altostratus — Wrong on both halves of the name. 'Alto' places it in the middle level, roughly 6,500 to 20,000 feet, and 'stratus' means a featureless grey sheet through which the Sun looks like a dim disc — nothing puffy or rippled about it.
- (b)Cirrostratus — The height and the ice crystals are right, but the form is wrong. Cirrostratus is a thin, smooth, almost transparent veil that covers the whole sky and produces haloes round the Sun and Moon; it has no cloudlets and no mackerel pattern.
- (c)Altocumulus — The puffy heaped form is right but the level is wrong — 'alto' means middle cloud, well below the 20,000 to 40,000 feet the stem specifies. Altocumulus cloudlets are also larger and, unlike cirrocumulus, are shaded on their undersides.
Clouds are classified by height band and by form. The height prefixes are 'cirro' for high clouds, above about 20,000 feet, 'alto' for middle clouds and no prefix for low ones; the form roots are 'cumulus' for heaped convective clouds, 'stratus' for layered sheets and 'nimbus' for precipitating clouds. High clouds are cold enough to be made of ice crystals, which is why they are thin and white rather than dense and grey. Cirrocumulus is the one high cloud with a heaped, granular texture, and it usually appears as sheets or patches of tiny cloudlets in regular rows.
Read the name apart and the answer falls out. Two of the three clues in the stem are about level ('high', '20000 feet and 40000 feet', 'ice crystals'), which eliminates both alto options at once, and the third is about form ('puffy', 'ripples', 'fish scales'), which eliminates cirrostratus. That leaves cirrocumulus without needing the nickname at all — though 'mackerel sky' is worth memorising because it is one of the few cloud nicknames examiners reuse. One useful cross-check: cirrocumulus is the one high cloud that carries a small amount of supercooled water alongside its ice, and its cloudlets never cast shadows on one another, which is what makes it look uniformly bright.
- Cirrocumulus occurs at about 5 to 12 km (roughly 16,000 to 39,000 feet) and is composed mainly of ice crystals.
- A sky of finely patterned cirrocumulus is called a 'mackerel sky' or 'herringbone sky'.
- 'Cirro' means high cloud, 'alto' means middle cloud, 'cumulus' means heaped and 'stratus' means layered.
- Cirrostratus, the other common high cloud, is a smooth veil that produces solar and lunar haloes.
- Reading 'cumulus' in the name and jumping to altocumulus without checking the height band the stem gives.
- Confusing cirrostratus with cirrocumulus — both are high and icy, but only cirrocumulus is granular and rippled.
- Assuming a high cloud must be pure ice; cirrocumulus carries a little supercooled liquid water too.
Asked as a three-clue identification item — CDS has run this exact format for cumulonimbus in 2023-I and for cotton-wool clouds in 2025-I.
During a thunderstorm, the thunder in the skies is produced by the 1. Meeting of cumulonimbus clouds in the sky 2. Lightning that separates the nimbus clouds 3. Violent upward movement of air and water particles Select the correct answer using the codes given below.
- (a) 1 only
- (b) 2 and 3
- (c) 1 and 3
- (d) None of the above produces the thunder
Answer(d) None of the above produces the thunder — thunder is the shock wave from air explosively heated by a lightning discharge.
Same family of clouds, tested on the physics rather than the name — worth pairing because cumulonimbus is the cloud CDS most often sets against cirrocumulus in identification items.
CDS_GK_2023_I_Q1032023Consider the following characteristics of a cloud type : 1. They are born through convection. 2. Only cloud type that can produce hail, thunder and lightning. 3. They are large cauliflower-shaped towers, often ‘anvil tops’. Identify the type of cloud on the basis of the given characteristics.
- (a) Stratocumulus
- (b) Cumulonimbus
- (c) Cirrocumulus
- (d) Nimbostratus
Answer(b) Cumulonimbus
The identical three-clue format one year earlier, and cirrocumulus appears there as a distractor — read the two together and the height-plus-form decoding becomes automatic.
CDS_GK_2023_II_Q982023Which of the following is the correct order of clouds in ascending order (lowest to highest) of height from surface? 1. Cirrocumulus 2. Nimbostratus 3. Cirrus 4. Altostratus Select the correct answer using the code given below:
- (a) 1, 2, 4, 3
- (b) 2, 4, 3, 1
- (c) 3, 2, 1, 4
- (d) 2, 4, 1, 3
Answer(d) 2, 4, 1, 3
Tests the same height ladder from the other direction — nimbostratus low, altostratus middle, cirrocumulus and cirrus high — which is exactly the ordering that rules out the two 'alto' options here.
- practice — not a real PYQ
Which one of the following clouds produces the halo often seen around the Sun or the Moon?
- (a)Cirrostratus
- (b)Stratocumulus
- (c)Nimbostratus
- (d)Altocumulus
Answer(a) Cirrostratus — refraction through its ice crystals forms the 22-degree halo; the other three are too low and too water-rich.
- practice — not a real PYQ
In cloud nomenclature, the prefix 'alto' indicates a cloud of which height family?
- (a)Low cloud
- (b)Middle cloud
- (c)High cloud
- (d)Cloud of vertical development
Answer(b) Middle cloud — 'alto' marks the middle level, roughly 6,500 to 20,000 feet, while 'cirro' marks the high family.