YUBA COUNTY – While most people were trying to stay out of the rain on Thursday, a group of researchers was out in the thick of it launching weather balloons to better understand atmospheric rivers.

Yuba Water Agency has been partnering with the Center for Western Weather and Water Extremes for the last five years. They've been researching atmospheric rivers to improve forecasts while simultaneously using that data to better operate Northern California's reservoirs and reduce the risk for floods.

This partnership is using technology normally applied to study hurricanes, to study atmospheric rivers. Part of that research includes weather balloons to monitor atmospheric conditions.

"We're reducing flood risk for the people of Yuba County," said the director of resource planning for Yuba Water Agency John James.

Yuba Water Agency is working on building another spillway at the New Bullards Bar Dam, specifically for atmospheric rivers, which historically are the storms that bring the most rain.

"And that would actually take these forecasts and convey the water downstream ahead of time, more so than we have right now," James said.

That way they can move more water in advance to protect the people in the county and reduce river levels in the valley. Improving forecasts is a top priority to better operate the spillways. Weather balloons are a helpful tool in improving forecasts.

"It's important the balloon be filled approximately the same volume every launch so it goes up to the atmosphere at the same rate," said lead engineer for the Center for Western Weather and Water Extremes Douglas Alden.

The idea is to send the balloons up with a radiosonde and a GPS to track the whereabouts of the balloon to understand pressure and wind patterns during an atmospheric river.

"Is this storm going to impact our watershed and do we need to release water from the reservoir ahead of it? Or this storm going to be going to the south and we should save that water because we need it comes summertime?" Alden said.

Weather balloons have the potential to reach up to 82,000 feet before pressure builds up and it pops, floating back down to the earth.

"The pressure in the atmosphere decreases in elevation and that means the balloon will continue to expand," Alden said, "by the time it gets up to where it pops, it's probably the size of a small minibus."

Atmospheric rivers tend to be narrow and dynamic, and any slight shift in direction could impact which watershed sees the most rain. It's best to know ahead of time where it's going, especially in a place like Yuba County which is prone to flooding.

"Once the balloon gets above the atmospheric river, that's really useful information for the weather forecast models. With this, we've demonstrated we can provide enough lee time so they can be more effective in those management decisions," Alden said.

The engineers are launching balloons every three hours until the atmospheric river ends.

Yuba Water Agency says the second atmospheric river spillway should be operational in the next four to five years using data compiled from days like Thursday.