Cirrus clouds themselves do not bring rain to the ground, although they do cause precipitation high in the atmosphere.
Understanding Cirrus Clouds and Precipitation
While cirrus clouds are often associated with fair weather, they play a role in the larger atmospheric processes that can eventually lead to precipitation. Here's a breakdown:
- Formation: Cirrus clouds form very high in the troposphere, where temperatures are extremely cold. This causes water vapor to freeze into ice crystals.
- Precipitation (but not rain): According to the reference, cirrus clouds do cause precipitation in the form of these ice crystals.
- Sublimation: These ice crystals, however, almost always sublimate (turn directly into water vapor) before reaching the ground. This is because the air below the cirrus clouds is usually too dry and warm.
Why They Don't Bring Rain (Directly)
The key is the sublimation process. The ice crystals formed in cirrus clouds don't make it to the surface as rain or snow.
What Happens Instead?
- Sign of Change: Cirrus clouds can be an indicator of an approaching weather system.
- Precursors to Storms: They can sometimes be precursors to larger storm systems, meaning other cloud types (like cumulonimbus) may follow and bring precipitation.
- Ice Nuclei: The ice crystals formed in the upper atmosphere by cirrus clouds may act as ice nuclei, helping to form raindrops in other clouds lower down if the atmospheric conditions are right.
Cirrus Clouds: In Summary
| Feature | Description |
|---|---|
| Composition | Ice crystals |
| Altitude | High in the troposphere |
| Precipitation | Yes, as ice crystals (but they sublimate) |
| Rain-Bearing | No, the precipitation doesn't reach the ground as rain |
| Weather Indicator | Can indicate an approaching weather system |
