Recently, there was an atmospheric river storm headed toward southern California which unleashed life-threatening floods and landslides in the region.

About Atmospheric River:

  • Atmospheric rivers represent elongated, concentrated corridors in the atmosphere that facilitate the transport of moisture from tropical regions to higher latitudes.
  • It accounts for a staggering 90 percent of the global moisture movement from the tropics towards the poles, establishing them as the foremost conveyors of freshwater on Earth.
  • It occurs when overarching weather patterns align to form narrow channels or filaments, characterized by intense moisture transport.
  • Simultaneously, the Earth may experience ten or more atmospheric rivers, showcasing the widespread influence of these phenomena across the globe.
  • Among the notable atmospheric rivers, the most significant is the Pineapple Express viz. renowned for transporting moisture from the tropical Pacific, encircling Hawaii, and delivering it to the West Coasts of the United States and Canada.

Some features of the atmospheric river:

  • These atmospheric rivers exhibit dimensions ranging from 250 to 375 miles in width and can extend over a thousand miles in length.
  • Notably, they manifest more frequently on the East Coast compared to the West Coast because it coincides with the winter season in each respective hemisphere, and also aligns with the heightened prevalence of extratropical cyclones.
  • On average, an atmospheric river transports a volume of water vapor approximately equivalent to the average flow of water at the mouth of the Mississippi River, the second-longest river in North America.

As atmospheric rivers encounter topographical barriers or intersect with local atmospheric dynamics, they are compelled to ascend.

  • During this ascent, the moisture they carry undergoes cooling and condensation, resulting in the potential for intense rainfall or snowfall.

When atmospheric rivers traverse over land, they induce conditions akin to hurricanes, featuring intense and rapid rainfall, cyclone-force winds, and notably elevated wave heights.

  • While these rivers play a crucial role as a significant source of rainfall, they also pose hazards, contributing to flash flooding, mudslides, and landslides that can lead to loss of life and property destruction.

In summary, atmospheric rivers, while vital for precipitation, carry both benefits and risks, emphasizing the importance of understanding and managing their impacts on the environment and society.

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