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Freezing fog expected to lift

A persistent layer of fog in the valley that caused flight delays and cancellations should be a thing of the past after today, with advancing weather systems ready to break up the stagnant air.

Medford airport Director Jerry Brienza said the fog continued to cause problems Wednesday morning, and fog-dispersing equipment was on the fritz.

“We had delays and a few cancellations,” he said.

At the Medford airport, equipment used to disperse the fog has been sidelined because the price of helium has shot up, and because CASPER (Cable Attached System Providing Effective Release) needed $20,000 in repairs.

“Even when we took CASPER out, it worked sometimes, sometimes it didn’t,” Brienza said.

CASPER involved sending up a balloon that released helium, which caused the moisture in the air to turn to snow. The price of helium will be prohibitively high for about two years, he said.

Since the University of Utah patent for the carbon-dioxide dispensing mechanism expired, his maintenance crew has been busy fabricating its own version of the device.

“We built it for a few hundred dollars,” he said. “The cannisters only cost $55 each to fill, and they run for four or five hours.”

On Wednesday, the maintenance crew removed the CASPER unit from the back of a pickup truck. The new carbon-dioxide dispenser was being finished up and will be tested Thursday morning, if there’s fog.

Basically, a nozzle sprays carbon dioxide up to about 100 feet, clearing a swath through the foggy air along the runway. Instead of requiring up to three employees to operate CASPER, the new unit will require only a driver to travel up and down the runway.

Brienza said both CASPER and the carbon dioxide units are particularly effective when the temperature hits single digits. In the teens, they’re both moderately effective, depending on wind and moisture conditions. When temperatures hit the 20s, they are less effective.

The National Weather Service expects some wind in the valley today, but there’s a slight chance of rain Friday, with more moisture expected Saturday.

“It won’t be as much as on Christmas eve,” said Misty Firmin, a meteorologist with the Weather Service based near the Medford airport. “The weather should be getting more active and staying active into next week.”

The Rogue Valley has been a bit on the dry side this season, with 5.2 inches of rain recorded since the water year began Oct. 1. That’s 2.53 inches below normal.

“We had a pretty dry October and November,” Firmin said.

The previous water year was also dry, with only 11.47 inches falling, far less than the 18.5 inches measured at the airport in a typical year.

Snowpack has been averaging up to 70 percent of normal, but readings from Crater Lake aren’t available because of the partial federal government shutdown.

The valley has had below-normal rainfall four of the past five years.

Reach reporter Damian Mann at 541-776-4476 or dmann@rosebudmedia.com. Follow him on www.twitter.com/reporterdm.

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