What is an atmospheric river?
The $214.8 billion state budget California lawmakers approved on Thursday sets aside more than $9 million for the study of atmospheric rivers, a type of strong weather system that was largely responsible for dramatic flooding in Northern California earlier this year.
The state-Senate amended revision to Gov. Gavin Newsom’s 2019-20 budget added $9.25 million, allocated to the Department of Water Resources’ state water plan and requires that that amount be available for the “Research, Mitigation, and Climate Forecasting Program to improve observations, forecasts, and decisions in support of atmospheric river precipitation events.”
The $9.25 million appropriation had been approved by the Assembly committee on Water, Parks and Wildlife by a unanimous 14-0 vote in March. Democratic Sen. Bill Dodd pushed for its inclusion in the final budget and announced the addition Wednesday.
An atmospheric river, sometimes called an “ARkStorm” by the U.S. Geological Survey and other agencies, is defined by the National Oceanic and Atmospheric Administration as “relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics.”
The ones that reach California are streams of moisture being pulled by wind from the tropics to the West Coast. Most are weak systems, but the strong ones can cause heavy wind gusts and flash flooding, as was seen during continuous downpours January through March of this year.
The rivers themselves span anywhere form 250 to 370 miles wide, according to the NOAA. Pineapple express is a well-known form of atmospheric river, taking moisture from Hawaii to the West Coast.
The Atmospheric Rivers: Research, Mitigation, and Climate Forecasting Program was created within the Department of Water Resources in 2015 by Senate Bill 758.
SB 758 stated that the program would “research climate forecasting and the causes and impacts that climate change has on atmospheric rivers, to operate reservoirs in a manner that improves flood protection in the state, and to reoperate flood control and water storage facilities to capture water generated by atmospheric rivers.”