An atmospheric river is a long, narrow region in the atmosphere that can transport moisture thousands of miles. They can be beneficial, providing water to fill reservoirs and build snowpack. California, Oregon and Washington rely heavily on atmospheric rivers for their annual water supply which regularly swings between boom and bust. Failing to materialize, droughts often follow-especially in California, where they account for over 50% of total annual precipitation. But they can also generate so much precipitation over a short period that they cause flooding, with an average of $1.1 billion in flood damages yearly in the western U.S.
Collapse of two ice shelves on the Antarctic Peninsula over the last quarter-century were probably caused by these rivers. The Larsen C shelf—fourth-largest ice shelf in Antarctica, and still mostly intact–could eventually suffer the same fate. These rivers are expected to become more intense as the world warms.
cnn.com/2022/04/11/weather/weather-news-severe-blizzard-atmospheric-river-wxn/index.html
research.noaa.gov/article/ArtMID/587/ArticleID/2852/Study-previews-how-climate-change-may-alter-rain-making-atmospheric-rivers-by-2100