The storms now pummeling Sonoma County are being driven by "rivers in the sky," low-lying streams of moisture which account for half the rainfall that falls on coastal California and has been blamed for most Russian River flooding.
It is a phenomenon scientists have been grappling to understand since 1998 and, with an array of new coastal observation stations and satellite imaging, are using Sonoma County and the storms this week as a test case.
"It basically comes up from the equator, a narrow band of extremely high water-content air that gets focused in one direction, like a fire hose," said Jay Jasperse, Sonoma County Water Agency chief engineer. "It is basically as the term suggests, a river of water in the atmosphere. We are in one of the prime areas to receive it."
Jasperse and scientists from the National Oceanic and Atmospheric Administration on Thursday were tracking the storms at NOAA's Earth Research Laboratory in Boulder, Colo.
The Water Agency has spent $300,000 and NOAA $270,000 for these studies, which are meant to eventually strengthen long-range forecasting, and help flood control and frost protection.