Ivor, Borth and Ynyslas’ Katabatic Wind

Along with the rest of the country we have been enjoying some gorgeous spring weather recently. Clear blue skies all day long and some of the most amazing sunsets and sunrises with spectacular oranges, pinks and purples. It has been quite cold too, especially at night which leads to a local phenomenon of a katabatic wind, affectionately known as Ivor here in Ynyslas and Borth.

It works in a similar fashion to a sea-breeze in the summer, but in the opposite direction and with more force. At night the temperatures in the hills can drop significantly, often reaching minus numbers and maybe even down to minus 8-10ºC. The sea however remains at a fairly constant temperature and is currently around 9ºC. That is a huge temperature difference. The sea warms the air above it which then rises, and cooler air from inland moves in to take its place, creating an offshore wind. As the sun rises in the mornings, it rays reflect off the surface of the sea further raising the temperature of the air above it which drives the wind even faster. This is the exact opposite to the summer sea-breeze effect, but the larger temperature difference increases the effect making the winds stronger.

On top of this, Ivor, the katabatic wind has gravity on its side (unlike the sea-breezes in the summer). The cold air in the hills sinks into the valleys and flows along them just like a river would. Gravity, coupled with topographic funneling in association with winds driven by a temperature gradient can produce some pretty startling effects here, with winds in excess of 20 knots when everywhere else is calm. If this also occurs on a day when there is a general E-NE wind direction then we often gets winds in the 30-40 knot range. More than enough for most people and perfect for those of us who windsurf and Kitesurf.

6 Responses

  1. Avatar forComment Author Garry Goodwin says:

    Finally met up with Ivor on Satuday, high tide was early morning and a few kitesurfers and one windsurfer, the windsurfer was on wave kit and a 4.5m sail, i waited till the tide receded and the wind dropped! I was thinking the day was done then it started to fill in so I rigged a 7.0m sail and headed out by this time the creek was quite shallow and narrow but the direction was good, I got 2 hours sailing in different parts of the creek with 2 different fins till I was completely overpowered, Great day in the spring sunshine!

  1. Wednesday, April 22nd, 2020

    […] time for the bees and for beekeepers alike. It should be and would be if it weren’t for Ivor our local katabatic wind. He’s been blowing his socks off with wind speeds exceeding 50 knots for days on end. No […]

  2. Saturday, August 13th, 2022

    […] forecast was likely to drop to less than 10 knots by that time of day. Still, I had faith in our local katabatic wind called Ivor. As you can see, temperatures were forecast to be high and the hazy sunshine would lead to perfect […]

  3. Monday, February 27th, 2023

    […] warmed up though and with an Easterly forecast I had a few contingency plans in place. I know what Ivor our local katabatic wind can do when an Easterly is forecast, so a few additional plans are always […]

  4. Tuesday, January 9th, 2024

    […] sun, sea and sand. It was just turned up a notch thanks to the fact that I was sharing it with Ivor, our local Katabatic wind…. he’s a […]

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Alan Cole

Alan is a Freelance Website Designer, Sports & Exercise Science Lab Technician and full time Dad & husband with far too many hobbies: Triathlete, Swimming, Cycling, Running, MTBing, Surfing, Windsurfing, SUPing, Gardening, Photography.... The list goes on.

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