Meteorology student Jackson Yip pulls the rig off of Highway 299 onto an open field, about 5 miles from the fire line, and gets to work inflating a small weather balloon -- about four feet across. It carries a transmitter the size of an eyeglass case, called a radiosonde, that will send data back to the truck. He lets it go and it shoots into the air.

"That’s a good sight. Come on, keep goin’, keep goin’!," urges Clements.

It will keep going, sampling and transmitting data back once every second, until it reaches 40,000 feet or more above the earth. The fire lab crew will transmit their data to the meteorologist on duty at the command post, where it can help form a better picture of conditions aloft.

Launch sites for weather balloons are "few and far between," according to Clements, so the team's ability to launch on site was a boon to the "i-met," the incident meteorologist who asked them to do so.

"Wow--look at that," Clements exclaims, as the information starts to form a picture. The first thing they notice is a strong inversion: a layer of air about 9,000 feet up that’s warmer than the air below.

"The air’s really, really warm above," he observes.



That warm air acts as a lid on the lower atmosphere, which helps explain why the entire Sacramento Valley seems to be enshrouded in a yellow, smokey haze. But what the team is really looking for, are signs that the fire’s behavior might be changing.

"If you have a very convective day, let’s say, in the atmosphere, where a lot of vertical motion is occurring," Clements explains, "that can impact the fire behavior."

One thing they can spot is something called a “velocity couplet,” where winds above the fire are moving in opposite directions, just meters apart. That indicates rotation, and the possible formation of fire “tornadoes,” like the one that added to the devastation near Redding.

They’re not seeing that on this day -- but as the information comes in, it reveals something else that’s potentially dangerous.