---
title: "Various forms of precipitation"
subject: "Engineering Hydrology"
chapter: 2
key: "semester_5/engineering_hydrology:forms-of-precipitation"
source: https://www.bctengineer.com/q/semester_5/engineering_hydrology/forms-of-precipitation
site: BCT Engineering
---

# Various forms of precipitation

Engineering Hydrology · Chapter 2: Precipitation

- Asked in: 2067 Mangsir (old course), 4 marks
- Video: [Types of Precipitation and Rain Gauges | Engineering Hydrology](https://www.youtube.com/watch?v=m_ALjsA1Als) — APSEd
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/engineering_hydrology/forms-of-precipitation
- Whole chapter: https://www.bctengineer.com/md/semester_5/engineering_hydrology/chapter-2

## Question

Describe various forms of precipitation.

## Short answer

Precipitation falls as rain (liquid >0.5 mm), drizzle (<0.5 mm), snow (ice crystals), sleet (ice pellets), glaze (freezing rain), and hail (ice lumps 5–50 mm). Rain and snow contribute most to water resources.

## Answer

Precipitation is any form of water that falls from the atmosphere to the earth. The main forms are:

| Form | Description |
|---|---|
| **Rain** | Liquid drops larger than 0.5 mm in diameter; the most common form. Light (< 2.5 mm/h), moderate (2.5-7.5 mm/h), heavy (> 7.5 mm/h) |
| **Drizzle** | Very small drops (< 0.5 mm) falling slowly, usually from stratus clouds |
| **Snow** | Ice crystals joined into flakes, falling when the temperature is below 0 °C; important in Himalayan basins |
| **Sleet** | Frozen or partly frozen raindrops (ice pellets) from rain passing through a cold layer |
| **Glaze (freezing rain)** | Rain that freezes on contact with a cold surface, forming an ice layer |
| **Hail** | Lumps of ice 5-50 mm or more from cumulonimbus clouds, made by repeated lifting in strong updrafts |
| **Dew, frost, fog drip** | Small deposits by condensation on cold surfaces (not true falling precipitation, but sometimes counted) |

Of these, rain and snow contribute most to the water resources of Nepal.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What distinguishes rain from drizzle?
   A. Rain is frozen
   B. Drizzle is heavier
   C. Drizzle falls from cumulonimbus
   D. Rain drops > 0.5 mm; drizzle < 0.5 mm
   Answer: D. Rain drops larger than 0.5 mm; drizzle is very small and slow. (Key point: Rain vs drizzle)

2. How does hail form?
   A. Repeated lifting in strong updrafts in cumulonimbus
   B. Rain freezing on surfaces
   C. Condensation on cold surfaces
   D. Snow melting
   Answer: A. Hail lumps of 5-50 mm grow by repeated lifting. (Key point: Hail)

3. What is glaze?
   A. Ice pellets
   B. Rain freezing on contact with a cold surface
   C. Fog drip
   D. Large snowflakes
   Answer: B. Freezing rain forms an ice layer. (Key point: Glaze)