THUNDER BAY — Heavy, wet snow that built up at an aviation radar site resulted in some minor flight disruptions in the Thunder Bay area last Thursday and Friday.
The radar facility is located just north of the city.
According to a Transport Canada Civil Aviation Daily Occurrence Report, Thunder Bay Airport experienced a radar failure at 5:40 p.m. on Oct. 3, and service wasn't resumed until 8:30 a.m. on Oct. 4.
Nav Canada spokesperson Brian Boudreau said "There was a snow accumulation on the dome of the radar unit," and it took until the next morning for a crew to clear it away.
"The radar unit is remote, and in the dark it's not safe for workers to clear the snow. They waited 'til daylight to do so," Boudreau said.
He explained that snow can affect the accuracy of radar equipment, "so as soon as that happens, as soon as accumulation is evident, as a safety precaution it's shut down."
Nav Canada is a private company that owns and operates the country's civil air navigation service.
The Transport Canada report on the Thunder Bay incident states "Numerous arrivals and departures delayed," but Thunder Bay Airport CEO Ed Schmidtke told Tbnewswatch the airport "did not notice an exceptional number of delays."
The maximum length of any delay was 10 minutes, Schmidtke said.
A Transport Canada spokesperson told Tbnewswatch the department doesn't keep statistics on radar failures due to inclement weather.
"In most cases, a radar system can handle snow, but can be affected by heavy and wet snow which can stick to the radar dome," Alexandre Desjardins said.
He explained that when other radar sources are available in an area, alternatives can be used to provide air navigation services.
"In this incident, air traffic was affected as there was no other radar source available until the radar at the Thunder Bay Airport regained its full capacity," Desjardins said.
Boudreau suggested radar shutdowns due to snow accumulation are rare but the Nav Canada spokesperson said he did not have immediate access to any relevant data base.