Atmospheric River

Extracted Attributes

• Width

  250 to 375 miles

• Length

  Over 1,000 miles

• Synonyms

  Tropical plume, moisture plume, water vapor surge, cloud band, tropical connection

• Global Frequency

  4 to 5 active at any given time

• Primary Components

  Water vapor and strong low-level winds

• Moisture Transport Capacity

  Equivalent to the liquid water flow at the mouth of the Amazon River

• US West Coast Precipitation Contribution

  30% to 50% of annual precipitation

Timeline

• Start of a sixty-year study period (ending 2010) showing that 60-74% of persistent droughts in the Northwest US were ended by atmospheric rivers. (Source: USDA Climate Hubs)

  1950-01-01

• The Atmospheric River Reconnaissance (AR Recon) program begins using aircraft to study atmospheric rivers over the Pacific Ocean. (Source: Scripps Institution of Oceanography)

  2016-01-01

• David Friedberg discusses the ArkStorm 2.0 atmospheric river model as a catastrophic threat to California in All-In Podcast Episode 163. (Source: Document ebe1f88d-428a-4f23-a40c-fcfb4a705668)

  2024-01-26

• NOAA and UC San Diego conduct global research flights using Gulfstream IV aircraft to improve atmospheric river forecasting. (Source: Scripps Institution of Oceanography)

  2025-02-01

Atmospheric river

An atmospheric river (AR) is a narrow corridor or filament of concentrated moisture in the atmosphere. Other names for this phenomenon are tropical plume, tropical connection, moisture plume, water vapor surge, and cloud band. Atmospheric rivers consist of narrow bands of enhanced water vapor transport, typically along the boundaries between large areas of divergent surface air flow, including some frontal zones in association with extratropical cyclones that form over the oceans. Pineapple Express storms are the most commonly represented and recognized type of atmospheric rivers; the name is due to the warm water vapor plumes originating over the Hawaiian tropics that follow various paths towards western North America, arriving at latitudes from California and the Pacific Northwest to British Columbia and even southeast Alaska.

Web Search Results

• Atmospheric Rivers - NASA Earthdata

  Atmospheric rivers are narrow, elongated corridors of concentrated moisture transport that occur in the lower atmosphere, ahead of the cold front in an extratropical cyclone. They are the largest transport mechanisms of freshwater on Earth. Their significant contribution of rain and snow to the water budget of western states of the United States is vital for water storage and management decisions in the region. However, because atmospheric rivers can deposit significant amounts of precipitation [...] Atmospheric rivers are a part of the larger system of extratropical cyclones that transport heat and moisture from the tropics toward the poles. Conditions that contribute to their formation usually include high humidity levels, strong low-level winds, and a moist neutral atmospheric profile. They typically occur in the extratropical North Pacific/Atlantic, southeastern Pacific, and South Atlantic oceans, often making landfall on the west coasts of North and South America. Other regions that [...] Instruments aboard NASA’s Earth-observing satellites collect data that can be used to identify atmospheric rivers, such as water vapor, wind, and precipitation. Ground-based instruments like rain gauges and ground radars are also used to study atmospheric river characteristics and effects. By helping scientists identify atmospheric rivers, NASA’s data products further enable studies of topics such as climate change trends, floods, atmospheric processes, water management, and weather

• A Climate Expert Explains Why Atmospheric Rivers Are Causing ...

  Atmospheric rivers are narrow bands of concentrated water vapor in the atmosphere, typically extending from the tropics to mid- and high latitudes. These intense atmospheric moisture bands are invisible to the naked eye, but satellite instruments can help us see these “rivers in the sky” by using infrared sensors, which is how scientists visualize them. Atmospheric rivers are responsible for transporting large amounts of water vapor across the globe, particularly from the tropics to the poles. [...] Atmospheric rivers are often associated with strong low-level wind ahead of the cold front of an extratropical cyclone, particularly during the winter. When they make landfall in a region, atmospheric rivers frequently lead to heavy precipitation, which can be vital to a region’s water resource needs, but they can also pose serious risks for flooding and mudslides. [...] Once again, atmospheric rivers are drenching the state of California. While atmospheric rivers are endemic to the region and play a critical role in replenishing water supplies, their frequency and ferocity is on an upswing, says Mingfang Ting, professor of climate at the Columbia Climate School and climate scientist at Lamont-Doherty Earth Observatory. Ting’s current research focuses on understanding monsoon variability, the impacts of heat waves and the effects of extreme heat on agriculture

• DOE Explains...Atmospheric Rivers - Department of Energy

  Atmospheric rivers are large, narrow sections of the Earth’s atmosphere that carry moisture from the Earth’s tropics near the equator to the poles. On average, the Earth has four to five active atmospheric rivers at any time. They carry massive amounts of moisture. Each moves the equivalent of the liquid water that flows through the mouth of the Amazon River. When they reach land, atmospheric rivers release this moisture, producing heavy snow and rain. [...] Atmospheric rivers are an important part of the Earth’s climate. They are responsible for 90 percent of the movement of moisture from the tropics toward the poles. This means atmospheric rivers are a major factor in the formation of clouds and therefore have a significant influence on air temperatures, sea ice, and other components of the climate. [...] Moisture from atmospheric rivers shapes large parts of the world. Research indicates that they are responsible for more than half of the rainfall in parts of the coasts of North America, France, Spain, Portugal, the United Kingdom, South America, Southeast Asia, and New Zealand. As such, they are critical to plant and animal life, agriculture, and people as sources of water. But atmospheric rivers can also cause severe flooding due to the massive amounts of precipitation they release.

• Atmospheric Rivers in the Northwest | USDA Climate Hubs

  Atmospheric rivers, as their name implies, are large channels of water in the atmosphere. They vary in size but can be 250–375 miles wide and over 1,000 miles long. Some carry more water than the biggest river on land, the Amazon River. Atmospheric rivers play important roles in annual water supplies around the world. These weather events supply 30–50% of precipitation and account for 90% of south-north water vapor transportfor the U.S. west coast. In the northern hemisphere, this water [...] Atmospheric rivers are a natural part of the water cycle in the western U.S. and in the Northwest occur most often in the fall and winter. When they are beneficial, they bring much needed rain to the region. Between 1950 and 2010, between 60 and 74% of persistent drought ended when atmospheric rivers made landfall. Although these storms can be helpful, when they bring too much water at once, they can cause a lot of damage. In the Northwest, atmospheric rivers have been the cause of recent [...] Unlike physical rivers, atmospheric rivers transport water as vapor rather than liquid. Also, high- and low-pressure systems determine where they move. This means that models can be used to forecast where they will drop their water, but it is not certain. Because the movements of an atmospheric river can be unpredictable, it can be difficult to prepare for their arrival.

• Atmospheric River Research Flights Go Global

  Starting this year, the Atmospheric River Reconnaissance program (AR Recon), led by the Center for Western Weather and Water Extremes (CW3E) at UC San Diego’s Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration (NOAA), will coordinate flights to study atmospheric rivers across both the Pacific and Atlantic oceans. This expansion of AR Recon, which has studied atmospheric rivers using specially outfitted aircraft over the Pacific Ocean since 2016, is [...] Atmospheric rivers may be associated with wet winter storms on the West Coast of North America, but these ribbons of water vapor in the sky are a global phenomenon. They can end droughts or destroy homes with dangerous flooding, and they are projected to become more intense and destructive. Now, a new international effort will study and forecast these storms on a global scale. [...] # Atmospheric River Research Flights Go Global The Atmospheric River Reconnaissance program joins forces with research programs across the world to improve forecasts of extreme weather events Author Alex Fox Topics Hazards Share Inside the cockpit of a NOAA Gulfstream IV during an atmospheric river mission in February 2025. Image credit: Erik Jepsen/UC San Diego.