FALL STREAK Meaning and
Definition
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Fall streak is a meteorological phenomenon characterized by an elongated, narrow band or streak of ice crystals or snow falling from a cloud that appears to dissipate or evaporate before reaching the ground. It is often observed as a visible gap in a cloud formation, creating a distinctive streak-like shape. Fall streaks typically occur in certain cloud types, such as altocumulus or cirrocumulus clouds, where supercooled water droplets freeze and fall to the ground due to a process called ice multiplication.
The formation of fall streaks begins when a cloud contains a mixture of supercooled liquid droplets and ice crystals. As these ice crystals grow, they begin to fall, causing a localized reduction in water vapor. This reduction in vapor pressure further inhibits the growth of liquid droplets, resulting in the gradual dissipation of the cloud along the falling path of the ice crystals. The visible streak is created by the contrast between the evaporating ice crystals and the surrounding cloud.
Fall streaks are a relatively rare phenomenon and can be visually striking, often capturing the attention of observers. They are usually observed high in the sky, where the presence of ice crystals is more prevalent. Although fall streaks do not reach the ground as precipitation, they are an interesting atmospheric phenomenon that adds depth and variety to cloud formations.
