Altostratus Cloud
Scientific Name: Altostratus
Category: weather
Brief Description
A mid-level grey or blue-green cloud sheet or layer that often covers the entire sky and allows the sun to appear dimly, as through ground glass.
Characteristics
Greyish or bluish cloud layer covering all or part of the sky, having parts thin enough to reveal the sun vaguely, as through frosted glass. Does not produce halos.
Habitat
Middle troposphere, typically found between 2,000 and 7,000 meters (6,500 to 23,000 feet) above ground level.
When to Find It
Common worldwide across all seasons, frequently preceding a continuous rain or snow storm.
Conservation Status
N/A
Ecological Role
Acts as part of the Earth's global hydrological cycle and plays a role in regulating surface temperatures by reflecting incoming solar radiation.
Easily Confused With
Cirrostratus clouds (higher altitude, thinner, and produce optical halos around the sun) and Nimbostratus clouds (darker, thicker, and produce continuous precipitation).
Observation Tips
Look up when the sky takes on a uniform, watery grey appearance. Pay attention to how the sun looks; if it's like a bright disc behind frosted glass, it is likely altostratus.
Interesting Facts
Altostratus clouds are composed of a mixture of ice crystals and water droplets, even at temperatures below freezing where supercooled water droplets persist.