Lesson 2 Page 2
Completion requirements
Discover: What is
Precipitation
?
Rain, hail, sleet, and snow are formed in similar ways.
Snow and rain can be a real drag when you are caught outside, but the weather is always fun when you can make the best of it. Water falls from the sky in various forms: sometimes as water, sometimes frozen as soft crystals, sometimes frozen in hard chunks. But no matter the form of falling water, all can be called precipitation.
When water vapour condenses in the air, we see it as a cloud. A cloud is a collection of water droplets or ice crystals in the air. Dust has a small role in cloud formation because water vapour condenses onto dust particles.
Pixabay
If that liquid water falls to the ground, we have rain. However, sometimes it is not that simple. When water vapour condenses high in the air where the temperature is very cold, that water vapour can turn to ice. If the ice crystals fall to the ground, we have snow.
The ice crystals blow inside the cloud. Water molecules freeze into a wide variety of six-sided snowflake shapes. No two snowflakes have the same arrangement of frozen water molecules on the inside.
Like twins who look the same on the outside, but are different on the inside, snowflakes are unique.
Occasionally, we may have rain and snow falling at the same time—that is called sleet.
The ice crystals blow inside the cloud. Water molecules freeze into a wide variety of six-sided snowflake shapes. No two snowflakes have the same arrangement of frozen water molecules on the inside.
Like twins who look the same on the outside, but are different on the inside, snowflakes are unique.
Occasionally, we may have rain and snow falling at the same time—that is called sleet.
Video
Thunderstorms have such powerful updrafts that the air can hold ice crystals in the air, preventing them from falling. When this happens, the ice crystals get bigger and bigger, forming chunks of ice. Finally, when the updraft can hold the ice in the air no longer, the chunks of ice fall as hail.
Hail, like this falling near Camrose, Alberta, can be dangerous. Watch from 2:17 to 4:45 for the hailstorm. The rest of this video is daytime thunder and lightning in Alberta.
How can I describe precipitation?
Resources
- Website: Precipitation: stuff that falls from the sky
- Webpage: Life Cycle of a Thunderstorm
- YouTube Video: Cool Clouds
Aboriginal Connection
The Haida Gwaii (formerly Queen Charlotte) islands, surrounded by the Pacific Ocean, are very cloudy and rainy. Some parts of the islands are the wettest in Canada. They get rain an average of 267 days, and the west part of the islands can receive more than 4 metres of rain each year!