Why does a bit of snow have such an impact at Manchester Airport?

As temperatures plummeted across the UK, Manchester Airport faced significant disruption after it was forced to close its runways for several hours on three consecutive days due to heavy snow.

On Sunday morning (January 5) the airport's snow removal operations sprung into action for three hours, with snow-clearing teams deployed again the following morning - and for a third time on Tuesday.

Although each day the closures were temporary, with the runways reopening later in the morning, it did have a knock-on effect on flight schedules. Some journeys were cancelled and dozens more experienced delays of up to three hours.

Delays happen when an aircraft misses its take-off slot and has to wait for a gap in the schedule - which can take several hours. Aircraft arriving late at the airport also need time to prepare for their next outbound journey, impacting flight schedules too.

While normal flight schedules have since resumed, delays and cancellations can be devastating for passengers, whether it's impacting routine travel plans or a long-awaited holiday abroad.

Manchester Airport wasn't alone having to close its runways this week. Northern travel hubs Leeds Bradford and Liverpool John Lennon Airport had to pause operations to clear away snow.

But why does a little bit of snow impact Manchester Airport so much, when airports in much colder countries can operate as normal despite much harsher conditions?

A key factor is that we usually get a different type of snow in the UK, compared to colder countries. Described as 'wet snow', it's much more challenging to clear than the 'dry snow' found in chillier countries.

When temperatures are closer to freezing point, snow is wetter, which means it's more likely to turn into slush and ice, making it more slippery and more difficult to clear. When temperatures are lower than -2C, snow is drier and easier to clear.

Kathryn Chalk, an operational meteorologist at the Met Office, explaining the difference between the two, said: "The size and composition of a snowflake depend on how many ice crystals group together and this will be determined by air temperatures. Snowflakes that fall through dry, cool air will be small, powdery snowflakes that don't stick together. This 'dry' snow is ideal for snow sports but is more likely to drift in windy weather.

"When the temperature is slightly warmer than 0 °C, the snowflakes will melt around the edges and stick together to become big, heavy flakes. This creates 'wet' snow which sticks together easily and is good for making snowmen."

Manchester Airport's location makes it more prone to snowfall, too. It sits in an area known as the 'Cheshire Gap' - a stretch of low land that sits on the border between England and Wales. Showers that develop in the Irish Sea move across into Cheshire, while winds from the north west also contribute. Add in cold temperatures and it's the perfect recipe for snow.

Ice is a particular issue for runways as the temperature of the ground at night is colder than the air, meaning any moisture on the ground can soon turn into ice, even if its warmer than 0C. Unlike on roads and pavements, grit can’t be used as it can damage aircraft.

At Manchester Airport, the runway is treated with de-icing fluid to prevent any moisture from freezing, while the surface is also slightly grooved to create more traction for aircraft.

How does Manchester Airport deal with snow?

With more than 20 miles of runways and taxiways, clearing snow at the airport is not an easy task. When there is snow, the airport deploys its fleet of more than 30 snow-clearing vehicles and in order to fully mobilise it, the airport has to temporarily close the runways to ensure they can be cleared quickly and help operations to safely resume.

The vehicles include nine Combined Jet Sweepers which are equipped with 12m snow ploughs to the front and high-powered snow blowers to the rear, each worth more than £100,000 each.

The airport also has nine tractor-mounted ploughs, six snow brushes and three de-icers, used to spread de-icing fluid on runways and taxiways. Five gritters are also used on roads and walkways, but not on parts of the airfield used by aircraft.

During the winter months the airport puts on extra staff to provide support, including an adverse weather standby team who can be deployed depending on the forecast.

Even a small amount of snow can have an impact; just one inch of settled snow means the teams have to clear more than 7,000 cubic metres of snow from the runways. That’s a lot of snow.

How do they clear snow at airports in much colder countries?

Other European airports like those in Germany and Switzerland can be prone to wet snow, yet those in Nordic countries experience much colder temperatures, creating drier and finer snow.

Naturally, these locations experience a lot more of the white stuff than we do - for example Helsinki gets on average 97 snow days a year, far greater than the 13 days the UK could experience - and airports are significantly more equipped to deal with it.

Finavia, the firm which manages and develops 20 airports around Finland, including Helsinki, starts preparing for the winter season as early as the summer.

Helsinki Airport has a fleet of 200 vehicles for winter maintenance, including 21 sweeper blowers, 19 trucks for anti-skid operations and snow removal, 12 wheel loaders, 12 snow blowers, three friction tester vehicles and two motor graders. During the winter season sweeper blowers are used for up to 800 hours to clear the runways.

Maintenance teams have 13 minutes to clear runways of snow, although it's often achieved in 11 minutes. Closures of the runway are extremely rare.

As well as coping with Finland’s regular winter conditions, the airport also has a ‘targeted snow removal’ plan on days with abnormal snowfall. It involves cooperation between the maintenance team, air traffic control and ground handling companies, to clear aircraft parking spaces and ensure they can turn around on time.

While runway closures, flight delays and disruption are frustrating for passengers, the measures taken ensure the airport can operate as safely as possible during wintery weather, and help travellers get to their destination.

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