The infamous Nolan’s Brook claimed over 50 cars in 2019. Almost everyone could be put down to poor preparation. Take your time, do it right. Water bra or a tarp will do the trick. You might think this is stop water entering the engine bay, it doesn’t really but it does minimise it, until you stop of course then all bets are off. Most importantly, what it does do, it slows the flow of flooding water around the fan. When water floods the engine bay and the fan hits it while spinning at speed it bust and breaks up into pieces, sending chunks through the radiator and rendering you stranded. If you run a petrol this will help you minimise water around the electrics. You want to give all the electrics under the bonnet a good covering of WD40 or similar before going swimming in water this deep.
Connect a snatch strap to a recovery vehicle to give immediate assistance. This will save your vehicle from filling with water while you look around for a snatch strap. It does not take long for water to come in. Lower your tyres! In this instant we might lower pressure well below 20psi, perhaps down to 14-15psi depending on the situation. Maybe even more depending on the bottom and how much right foot you are going to use. You do not want to roll a tyre off the rim.
An important note. Even if you’re not towing a trailer, you want a water bra, a snatch strap and recovery vehicle at the ready with water this deep. Hope that tip helps you one day.
Good luck, see you out there.