Snowfall
Also called: Snow · Topic: Water in the Atmosphere: Humidity, Condensation, Clouds and Precipitation · NCERT: Class 11, Ch 10 "Water in the Atmosphere"
Meaning
Snowfall is precipitation in the form of snowflakes. It happens when condensation (water vapour turning into water or ice) takes place below 0 °C. The vapour turns straight into tiny six-sided (hexagonal) ice crystals. These crystals join to form flakes, which become heavy enough to fall. Snowfall is common at high latitudes and on high mountains. It matters because it feeds glaciers and snow-fed rivers, which keep flowing even in the dry season.
Example
In winter, western disturbances bring snow to the western Himalaya in Jammu and Kashmir and Himachal Pradesh. This snow feeds the glaciers that supply rivers such as the Indus and the Ganga.
Don't confuse with
- Sleet: Sleet is raindrops that freeze into small ice pellets as they fall through a freezing layer near the ground. Snow is made of ice crystals that formed inside the cloud.
- Frost: Frost is ice crystals that form directly on cold surfaces near the ground, when the dew point is at or below 0 °C. It does not fall from clouds.