Photo of snowy Sussex woodland trail Photo of snowy Sussex woodland trail

What is a Gap Wind?

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
What is a Gap Wind?

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!”

Illustration by Neil Gower and from the book The Secret World of Weather

Here is the same wind seen accelerating through the gap from within that woodland:

The gate I was standing by can be seen in the centre of the shot. This is the gap that the wind is accelerating through.

For more on Gap Winds and the other winds shaped by your local landscape, please see The Secret World of Weather: