Stratus clouds are nothing but the clouds at lower altitude. They are also called ‘strato-form clouds‘. In simple terms, it is the fog that is above the ground. These are mostly non functional due to its lower moisture content. Rarely they do cause rain or snow. They have colours ranging from white to grey depending on the moisture content in them. When people mention the climate as ‘Cloudy’ that means the sky is covered with stratus and the rain will follow soon within few hours.
Fact 1: Stratus cloud is usually found at the altitude as low as 2000 meters above the ground. These are formed when the fog are lifted due to sudden temperature changes.
Fact 2: When clouds combine with the stratus cloud they either form Cirrostratus, Altostratus, Nimbostratus or Stratocumulus.
Cirrostratus: is a thin sheet-like layer of cloud which is 18,000 feet above the ground. These are so thin that they only form a translucent in fact almost transparent layer in the sky. They can only be identified when they pass infront of the sun or moon because when they do so, a circle around the sun or moon is formed due to the bending of light rays which pass through these clouds.
Altostratus: These are formed 6,000 to 20,000 feet above the ground and are bluish grey in colour. These are so thick that rarely any sunlight will pass through them. May be the thinner section of these cloud will let a small amount of light through them showing a blur image of the sun. These type of stratus are usually found right before a storm.
Nimbostratus: This means perspiration producing clouds. These are found within 6,000 feet above the ground. They usually cause light to moderate drizzle. They will not cause heavy rain and they are not transparent.
Stratocumulus: These clouds are developed vertically and hence appear as rows of cotton balls from below. Due to its vertical arrangement, the top end might sometime cool down in winters and cause rain. Otherwise these rarely cause any perspiration.
Fact 3: Stratus of all kinds form the 50% of the annual cloud cover in Arctic regions that affects the energy emissions and absorptions through radiation.
Fact 4: When a stratocumulus element fuses into an even featureless sheet, ‘Mutatus mother clouds’ are formed.
Fact 5: The word ‘Stratus’ means blanket or a layer. The stratus clouds are called so because they are spread across the sky in a thin layer.
Fact 6: Sometimes the stratus sweep so low especially in the higher altitude regions, that they touch the ground and turn into fog. When they are little higher than the ground they can also form slight drizzle in such areas.
Fact 7: Often in urban areas, the stratus traps the dirt and pollution contents in them and as we know stratus rarely cause rain. As a result at the end of the day people feel sticky and dirty when the stratus passes over their city.
Facts 8: Sky watchers often find stratus boring since they do not form any patterns in the sky. But, these when combined with the other cloud layers can form some really interesting and beautiful patterns.
Fact 9: Stratus clouds are generally harmless to the aircraft. But they can make it difficult in being able to see through them. The Altostratus however can be dangerous to aircrafts because they may cause ice accumulation on the wings causing hassles in the flight.
Fact 10: The stratus clouds create a dull light effect often artificially set up by some filmmakers to create a certain mood with flattened look.