How extreme weather impacts your golf course

This article was featured in the Autumn 2018 edition of Your Course magazine

If we’re not coming off one of the hottest summers on record, we’re being drowned in a winter flood. Steve Carroll asks weather expert Mark Hunt why our climate seems so unpredictable.

Last winter was a washout, if it wasn't the onslaught of the Beast from the East, it was the never ending spells of rain that kept fairways and green sodden.

Gene Kelly might have been singing the rain, but relentless downpours were no laughing matter for those of us who wanted to get out on the course.

Summer is just as problematic. If it's not baking hot - and risking a hose pipe ban - it's thunder, lightning and flash floods.

What is causing these extremes in weather? Can it simply be put down to climate change?

From 2007 to 2023, weather expert Mark Hunt produced a weekly weather blog on meteorological patterns and how they affect turf. It became essential reading for course managers, greenkeepers and groundsmen.

So, who better to ask about why our climate seems so volatile?

There's a lot of debate about climate change, but is there any doubt in your mind that the weather patterns are changing?

I actually think the debate is irrelevant. My pet theory is that the nature of the Jet Stream has changed, and that's what is giving us different extremes of weather. People can argue that we may have experienced those extremes in the past, but we can't correlate that with the Jet Stream because we have only known about it since the early 1940s and we can't go back in history. Looking at why the weather has changed, whether it is climate change caused by man's activities or whatever, is slightly irrelevant. The challenge for us is how we deal with what we've been dealt.

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What is the Jet Stream?

The Jet Stream is a very strong air current in the high part of the atmosphere that flows in a meandering path from West to East. It typically separates the cold arctic air from warm tropical air. The Jet Stream can shift north or south and its position determines whether the warm or cold air dominate our weather patterns.

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We are getting more extremes of weather and that's leading to positives and negatives from a golf club's point of view. The main negative is turf disease activity. Diseases are far more aggressive and they are active at different times of the year than when I started in the industry in 1989.

We are seeing diseases we once saw in November now appearing in July and August. We are seeing diseases affecting grass that we have never seen before.

You only have to give the example of the run up to last Christmas. From the 22nd right through to Christmas Day we had four days that were conducive to disease. Most people are shutting up shop for the year, but some of our highest disease pressure was the week before Christmas. That was caused by a peak in the Jet Stream that allowed warm air to come up from the Mediterranean. We went up to 12 degrees at night with very high humidity and the combination of the two drives disease.

We are getting more of these peaks and troughs and that's because of the behaviour of the Jet Stream. We can’t prove if it has fundamentally changed, but it is undoubtedly what's affecting our surfaces.

A lot of people think the seasons have altered…

Just about everywhere I go, one of the biggest changes is the autumn season. Were getting warmer air later into the year.

Even if last autumn was a traditionally cold one and we had snow in December, we also had 12,13, and 14 degrees at night.

Autumn has definitely changed. October is more or less an extension of September and we don't really start getting cool nights and frost until November. It's very rare we get them any earlier.

In January, it was 13 degrees where I lived in the Midlands. If I had dropped you there and asked you what month of the year it was, you might have said March and that's not normal for us.

People say we had that 25 or 30 years ago, we had that in 1947 when we had the worst winter. I've looked at the data and we were nowhere close to that.

It's difficult to say for definite whether things have changed for good or perhaps we are just in a peak or a trough, but the seasons have definitely changed.

Whatever the debate, what we can all agree on is that the extremes of weather are much more than they used to be.

We have more moisture in the atmosphere because we are warming up. Sometimes we have these trough events where a low pressure system gets stuck over us and instead of moving across the UK and Ireland quickly it gets stuck and we get rain and rain and rain, which leads to these very high daily rain totals.

What do these pressures mean for our golf courses?

There's a multitude of things. Because we get very high levels of rainfall over a short period, you are asking the root zone of the green and elsewhere to drain quickly. You are asking them to be able to shift water quickly to remain playable. You can do that on a green if it is constructed the right way with proper drainage. But most golf courses away from the green don't have really well-drained fairways. You are exceeding what you can expect the grass or root zone to move through.

It's not like you have a small amount of rainfall at a time, it's a big dollop, and you've got to move it through the soil quickly, otherwise you'll see puddles and flooding.

We often exceed the parameters of what greenkeepers are able to maintain. They are having to do more aeration, more sand, more topdressing, to move water through quicker.

Secondly, and arguably the most significant, is disease management. We are getting more significant climatic drivers and at the same time we are getting legislation that is removing a number of different pesticides. So, we have got a perfect storm.

Greenkeepers have less in their armoury to control disease and have much more aggressive disease activity that comes on really quickly. Disease can move from affecting a plant to killing it in 48 hours because you have 18 or 20 degrees in October, which makes the disease more aggressive.

In the old days, you could see a bit of disease and decide whether you wanted to treat it or not. A lot of people would just grow it out. nNow, by the time you see it and if the conditions are right, it will scar down to the crown. If you get scarring in October, you might be left with it until March or April.

How much extra rain are we seeing these days than previously?

Figures are deceptive. If you look across a year, you might say we don't get any more rain than we used to. It's more the patterns of rainfall. So even in a month, you could say we had 70mm in July, which is an average, wettish July. But when you look closer, you might find those 70mm fell in just four days. You get these big dollops, rather than spread generally.

That is because we have more moisture in the atmosphere and we are getting these trough events where we get very high amounts over very short periods.

It's not necessarily that we get more rain across a year or a month. It's the pattern of the rainfall. You have got to look further than general figures.

The warmer temperatures in autumn are affecting growing seasons as well. You could have applied fungicide, but you're still cutting three times a week in October, so you are removing that fungicide quicker.

We did some tests in October 2017 versus October 2016 and fungicide was lasting about seven days less. Instead of it lasting three weeks, we were only getting a fortnight out of it.

That means two applications and a doubling of the cost, so tthere can be quite a large cost implication for our clubs.

If you have 30% more growth in October, that means you are going to have to cut and maintain the growth. That's more diesel, more man hours and more machinery hours.

It's not all bad news. In the third week of January this year, it was mild. I know a lot of people who were able to do aeration at a time of year when most golfers are just happy to get out and hit a ball. So from what I saw, we didn't have the Augusta effect.

They were taking advantage of a weather window, because they got growth that week and, their ground conditions allowed it, they could do some aeration and get recovery before the main revenue months started in March, April and onwards.

You could do the work then, instead of in March.

Is it easier then to get courses ready for the traditional opening because the growing season starts earlier?

Aprils are becoming very difficult from a grass growth point of view. In general, they are drier and cooler and so we may have a warm day but a frost at night. A golfer plays at midday and he's in short sleeves, but the greenkeeper who was cutting the greens in the morning, probably got frost on the machine. In those conditions, grass just doesn't want to grow.