What characterizes an atmospheric river?

An atmospheric river is characterized as a narrow corridor of concentrated moisture in the atmosphere. This phenomenon transports large amounts of water vapor from the tropics to mid-latitude regions, effectively acting like a river in the sky. Atmospheric rivers are crucial for delivering precipitation, particularly in the form of rain or snow, to various regions, often leading to significant weather impacts such as heavy rainfall and flooding when the moisture encounters mountain ranges or other geographical features.

Understanding the nature of atmospheric rivers begins with their ability to carry moisture over long distances. They can be hundreds of miles wide and extend thousands of feet into the atmosphere, making them essential for the global water cycle. This concentrated transport of moisture is what distinguishes atmospheric rivers from other weather phenomena, emphasizing their role in weather patterns and climate impacts.