What's the weather like there right now? I would consider the possibility of atmospheric ducting...
wattsupwiththat.com...

A GHOST train is driving residents in a rural parish round the bend, waking up sleepers with its constant rumbling along the rails.
And the really scary thing is, the nearest railway line is 15km away in Killarney.
Now frustrated locals in rural Beaufort, Co Kerry, are pleading with the Government to STATION investigators in the area in a bid to TRACK down the source of the sound.
Tradesman Barry Lynch, 43, said: “The first time we heard it was in April 2011 and it has been there 24/7 ever since.
“We are nearly gone out of our minds because we can’t get a decent night of sleep.
“It is very hard to describe what exactly we are hearing.
“It is as if an old ghost train is passing through the parish all day and every day.
“It is a real haunting noise and we are baffled.
“There are no mobile phone masts, windmills or generators in the area and the ESB has assured us that the problem is not due to high-tension wires.
“We thought it might be coming from water pumps installed by Kerry County Council but an engineer switched the pumps off for a trial period and the noise was still there.”