Whenever a wind is forced through a narrow gap it accelerates. This is true of all fluids, gas and liquid, it is the reason we put a thumb over the hose opening to make the water go further and also the reason why rivers flow faster on either side of an island.Tristan Gooley, from The Secret World of Weather
The audio on the video above is a bit hard to hear, so this is what I’m saying:
“It’s hard to imagine, but the winds out there, in the open field, even at the top of a hill, aren’t really very strong.
And the winds deep in the wood are almost non-existent. I’ve just been sitting in there for quarter of an hour, catching up on taking notes and there was a breeze, but that was it.
But where I’m standing just here, there’s a ‘gap wind’ where a wind is hitting both sides of the woodland and then barrelling through this gap here.
Gap winds can take a decent breeze and turn it into a howling wind. I mean look what it’s doing to the foliage there, it’s had the Alex Ferguson hairdryer treatment.
And yet in there [in the woods], I was watching seeds float by on a steady breeze.
That’s the joy of the Gap Wind!”
Here is the same wind seen accelerating through the gap from within that woodland:
For more on Gap Winds and the other winds shaped by your local landscape, please see The Secret World of Weather: