Which of the following statements regarding clouds is/are correct? 1. Clouds are classified on the basis of altitude and their form. 2. According to altitude they are classified as High, Middle and Low clouds. 3. Stratus, Nimbostratus and Stratocumulus are high clouds. Select the answer using the code given below:
- (a)1 only
- (b)1 and 2 only
- (c)2 and 3 only
- (d)1, 2 and 3
Correct — B, statements 1 and 2 only. Clouds are indeed classified by both altitude and form (statement 1), and by altitude they fall into high, middle and low families (statement 2). Statement 3 is false — stratus, nimbostratus and stratocumulus are LOW clouds, sitting below about 2 km, not high clouds; the high family is cirrus, cirrostratus and cirrocumulus. So only 1 and 2 are correct.
- (a)1 only — This drops statement 2, but the three-fold high/middle/low grouping by altitude is standard and correct.
- (c)2 and 3 only — This keeps the false statement 3 (those clouds are low, not high) and wrongly drops the correct statement 1.
- (d)1, 2 and 3 — This includes the false statement 3, which mislabels three low clouds as high clouds.
The World Meteorological Organization classifies clouds by the height of their base and by their form. By altitude there are high clouds (about 6-12 km) — cirrus, cirrostratus and cirrocumulus; middle clouds (about 2-6 km) — altostratus and altocumulus; and low clouds (below about 2 km) — stratus, stratocumulus and nimbostratus. By form they are cirriform (wispy), stratiform (layered) and cumuliform (heaped). Clouds of great vertical extent, such as cumulus and cumulonimbus, span several levels.
The examiner plants the trap in statement 3 by taking three genuine cloud names and mislabelling them 'high'. The name-prefix rule solves it — 'cirro-' marks high clouds and 'strato-' marks low layered clouds, so stratus, nimbostratus and stratocumulus flag immediately as low, making statement 3 false.
- High clouds are cirrus, cirrostratus and cirrocumulus — ice-crystal clouds at roughly 6-12 km.
- Middle clouds carry the prefix 'alto-' — altostratus and altocumulus at roughly 2-6 km.
- Low clouds include stratus, stratocumulus and nimbostratus, below roughly 2 km; nimbostratus brings steady rain.
- Cumulonimbus is a towering, vertically developed cloud that produces thunderstorms.
Stratus, nimbostratus and stratocumulus are LOW clouds, so statement 3 is false — only 1 and 2 are correct.
- Assuming stratus-family clouds are high — the 'cirro-' prefix marks high clouds, 'strato-' marks low layered ones.
- Thinking clouds are classified only by shape — altitude is the other axis of classification.
- Confusing nimbostratus (low, steady rain) with cumulonimbus (towering thunderstorm cloud).
Cloud questions test the altitude family (high/middle/low) and the name-prefix rule — cirro means high, alto means middle, strato means low layered.
Consider the following climatic and geographical phenomena: 1. Condensation 2. High temperature and humidity 3. Orography 4. Vertical wind Thunder-cloud development is due to which of these phenomena?
- (a) 1 and 2
- (b) 2, 3 and 4
- (c) 1, 3 and 4
- (d) 1, 2, 3 and 4
Answer(d) 1, 2, 3 and 4
Same topic of clouds — the UPSC item asks which phenomena build a cumulonimbus (thunder-cloud), one of the vertically developed cloud types in the classification this question tests.
- practice — not a real PYQ
Which one of the following is a high-altitude cloud?
- (a)Stratus
- (b)Cirrus
- (c)Nimbostratus
- (d)Stratocumulus
Answer(b) Cirrus — cirriform 'cirro-' clouds form high in the troposphere, at about 6-12 km.
- practice — not a real PYQ
Which cloud is chiefly responsible for thunderstorms with heavy rain and lightning?
- (a)Cirrostratus
- (b)Altocumulus
- (c)Cumulonimbus
- (d)Stratus
Answer(c) Cumulonimbus — a towering, vertically developed cloud that produces thunderstorms.