A mate of mine does this. He is a landscape gardener/groundsman by trade so has some of the necessary licenses for operating heavy machinery. If I recall he does 1 day training at the start of the winter then is on call when snow is forecast
I flew out of Gatwick recently and noticed a massive fleet of ploughs/tractors/etc - seems total overkill for a couple of days a year (if that) but I suppose you need loads for an area that large.
"Heathrow Airport to pay workers up to £435 a day to clear snow from runways over Christmas"
https://www.standard.co.uk/news/london/heathrow-airport-pay-workers-clear-snow-runways-b966765.html
"Anyone wishing to bag a well-paid job before the festive season can apply via jobs website Adzuna who raised awareness of the Heathrow role in a blog post"
absolute bullshit, there isn't a single job listed for snow clearance on their website