Here's a breakdown of why:
* Temperature: Low-altitude clouds form in the lower atmosphere, where temperatures are generally above freezing (0°C or 32°F).
* Water Vapor: The atmosphere contains water vapor, which is a gas. When this water vapor cools, it condenses into tiny liquid water droplets.
* Condensation Nuclei: These droplets form around tiny particles in the air, called condensation nuclei, which can be dust, salt, or other microscopic particles.
While most low-altitude clouds are composed of water droplets, some can contain supercooled water droplets which are liquid water below freezing. However, these are still primarily water-based.
Here are some examples of low-altitude clouds:
* Stratus: These are flat, featureless clouds that resemble fog.
* Cumulus: These are puffy, cotton-like clouds that often have flat bases.
* Nimbostratus: These are dark, gray clouds that produce continuous rain or snow.
* Stratocumulus: These are gray or white patches of clouds that look like rounded masses.
Note: While low-altitude clouds are primarily composed of water droplets, high-altitude clouds like cirrus clouds are composed of ice crystals due to the extremely low temperatures.
