Atmospheric Rivers

The importance of Atmospheric Rivers to California flooding can be found in the presentations presented at the Symposium. Go to the Speaker Index page and search the paper/presentation titles by speaker for "atmospheric". There are some additional links listed here.

Forecasting Atmospheric Rivers in California

This article, Unlocking the West's Weather Maker, highlights the research underway to improve the forecasting of atmospheric rivers in California and why it is important to do so.

Source for the Latest Atmospheric River Information

The Center for Western Weather and Water Extremes (CW3E) provides focused attention on atmospheric rivers (AR) impacting Western North America. Go to their website for the latest AR information and forecasts.

CW3E opened in 2013 and is part of the Scripps Institution of Oceanography at the University of California, San Diego.

Observing Atmospheric Rivers in Real Time

Atmospheric rivers (ARs) have been in the news as they have been bringing significant precipitation to California and the other West Coast states in December 2014. Real-time viewing of ARs as they travel across the Pacific Ocean is provided by the University of Wisconsin, Madison's MIMIC-TPW site. You can see real-time info or access the archives for specific dates back to 2007.

Learn About Atmospheric Rivers

A good place to start is: NOAA's Earth System Research Laboratory's Atmospheric River Information Page.

NASA-led Study Finds Climate Link to Atmospheric-River Storms

November 08, 2013

A new NASA-led study of atmospheric-river storms from the Pacific Ocean may help scientists better predict major winter snowfalls that hit West Coast mountains and lead to heavy spring runoff and sometimes flooding.

Details on NASA's Jet Propulsion Laboratory page, Study Finds Climate Link to Atmospheric-River Storms.

Hydrometeorological Report No. 37 (HMR-37)

One of the most important studies of weather patterns responsible for widespread flooding in California was published in 1962 as Hydrometeorological Report No. 37 (HMR-37). Prepared by Robert L. Weaver of the U.S. Weather Bureau (now National Weather Service), its title is: Meteorology of Hydrologically Critical Storms in California.

The importance of Weaver's work presented in HMR-37 is still significant in 2013. He identified three primary storm types:

Using the American River as an example, the ten largest floods from 1905 to 2012 (based on peak discharge) were caused by the low-latitude storm type. Research since Weaver completed HMR-37 tells us that this storm type is an Atmospheric River.

Download HMR-37 [PDF*, 14 MB] here.

* PDF files require a PDF reader. If your computer does not already have one, you can get Adobe® Reader.