Nov 25, 2013 9:55 PM by Russ Thomas - KPAX News
MISSOULA - Missoula International Airport Director Cris Jensen faced what he called an airport's worst nightmare just three months after starting on the job.
"The week of Thanksgiving 2005, we had a pretty severe fog event and we ended up losing about 60 flights that were diverted due to fog."
It was a weather event that created a financial blow in landing fees, passenger facility changes,at the restaurant, and in the gift shop - while also creating a hassle for travelers.
Jensen and his staff began searching for a solution. The answer came from one of his employees.
"He said, 'I have it all figured out,' and he dropped a stack of papers at my desk. And it was a fog seeding program by the University of Utah," said Jensen.
The studies showed that releasing liquid carbon dioxide into the air condensed the fog and made it precipitate out as snow. A Fog Seeder is mounted into the back of a pick-up truck and released in and around the airport's perimeter.
"We constantly have to adjust where we are spraying and trying to keep open a hole open over the approach end of the runway so that there is visibility for the pilots," airport mechanic Nate Cole explained.
The most success comes when the air temperatures is at or below 28 degrees, and one of the things Jensen and his staff had to look at was what harm - if any - the chemicals used have on the environment. Jensen says the benefits outweigh the concerns.
"It is liquid carbon dioxide; you know obviously carbon dioxide is a greenhouse gas. The benefit of the program is that instead of an aircraft flying in hold, so typically when an aircraft arriving at an airport and if we have fog and is not able to land, they'll go into a holding pattern and they will typically hold for a half-hour."
Multiply that by several planes circling over a short period of time, and the pollutants build quickly. Jensen says the sprayer uses only about two gallons of the chemical per hour. With the cost of the entire operation costing about $5,000 annually and a success rate of 70%, Jensen says saving just a few flights a year more than makes up the cost that would incur without fog seeding.
Since renting the Fog Seeding Equipment back in 2006, the airport has used about eight to 12 times a year on average.