Evaluating off-road obstacles

Michael Borg — 27 April 2018

Hands up, who’s been bogged to the axles in the middle of absolutely nowhere? I have, more times than I care to admit, and it bloody sucks! Sure, we can say it’s all part of the adventure, but let’s face it — nobody goes camping for the thrill of getting stuck. That being said, sometimes the terrain you’re in has a real knack for catching the nut behind the wheel, off guard. Like when that stinky old stale bog hole turns out to be a little deeper than you first thought, or the seemingly manicured green grass turns out to be a sea of eight-foot deep black soil! The good news is you can avoid the majority of nature's little 4WD traps if you know what to look for. I’m not saying a rush of adrenalin won’t bypass your brain and leave you hanging off the end of a snatch strap, but by following a few fairly simple rules of thumb, you just might avoid a real headache on your next trip. With that in mind, lets get stuck into it, one type of terrain at a time!


There are a few things to consider before you dive in the deep end of a water crossing; the depth and flow/current of the water are right at the top of the list. To break it down into simple terms — if you can’t walk it with ease, you shouldn’t drive it! Yep, if you’re walking across and the flow of water is dragging you off your line there’s a bloody good chance it’ll do the same to your vehicle, especially with a trailer in tow. If you fall into any deep holes, your 4WD definitely isn’t going to like it either, so suss it all out properly.

Now for the big question — How deep is too deep? Well, that all depends your vehicle, and how strong the current flow is. But know this, when a vehicle begins to float, the wheels no longer touch the ground and you no longer have traction or control. In fact, a study conducted by the University of NSW Water Research Laboratory, found that a large 4WD vehicle weighing 2.5T was able to be moved by water just 45cm deep with a flow speed of 3.6km per hour — that’s a flow of about 1m per second, when you do the maths! 

The entry and exit point will also need to be thoroughly checked out too. Look at things like how steep and slippery they are and what kind of position the vehicle could end up in as a worst-case scenario. Pay particular attention to how solid the river bank is too. If your feet break the muddy surface and start to sink, imagine what a few tonnes worth of 4WD will do to it!


Once again, the depth of the hole is the big one here. So when it comes to deciding whether to attempt a bog hole or not, make sure you check it out first. Now you could go for a walk in there, but lets face it — bog holes bloody stink! Not to mention the sorts of dangers that could be lurking beneath the surface (think sharp objects or wildlife), so you’re far better off poking a big stick in there for a while. Obviously you want to see how deep it is, but use this time to make sure there are no high or low spots, and the wheel tracks are both the same depth, so you don’t end up on a nasty angle. Oh, and make sure the wheel tracks themselves aren’t too deep; 4WD’s with large tyres have a bad habit of digging the wheel ruts deeper than usual, so your average 4WD ends up bottoming out and getting stuck.


Driving in snow can be absolutely unreal fun, but it can be super tricky to suss out properly. The main problem is you just don’t know what lies beneath the surface, and you can’t exactly poke a stick in there every metre or so for a few days of driving. So what can you do? Well, obviously, deep snow is just plain dangerous and should be avoided. Sticking to designated tracks and even just other vehicles tracks as much as possible is a great start too, eh? At least that way you minimise the chance of running over stumps or falling into holes. 

You’ll also want to look for landmarks or indications of how deep the snow is, or clues that could indicate a hazard before it’s too late. For example, if you spot a large tree trunk that’s been snapped in half, there’s a good chance the top portion could be lying across the track submerged under the snow.


Ok, so you’re at the bottom of a challenging rock step climb — what next? How do you know if you should attempt it, or instead, look for the chicken track? Well, the first thing to do is weigh up what could go pear-shaped before you commit. Ask yourself, “What happens if my rear wheels fall of the side of that rock? Will I end up on my roof?” When you’ve got a good idea of what you should be steering clear of, suss out a safe and feasible line or route to commit your vehicle to. You’ll want to look for a line that will keep all of your tyres firmly planted on the ground, and the vehicle relatively level in the grand scheme of things. Make sure you allow for a diminished turning circle if there’s a trailer in tow, too. Obviously, you’ll want to make sure your 4WD has enough ground clearance to clear the obstacles, but don’t stop there — check out how much traction is available. Are the rocks nice and grippy? Do they have a shined glazed surface coated with a layer of slippery mud?

The number one thing here is to weigh up the options and the risks involved before you hit the tracks. It’s too bloody late afterwards, eh?


Black soil has been catching the keenest of drivers out since horse and carriage days. Mainly because this deceiving little bugger can be a bottomless pit of slush, which will near-on swallow a 4WD whole! The problem is, it’s usually covered with a layer of lush vegetation so you don’t realise you’re in trouble until you’re reaching for the shovel. Not that it will help much, once you’ve cracked the surface, it can quickly become a full-scale recovery effort!

So the question is — what are the warning signs? How do you know where to steer clear of? Well, for a start, look for patches of overly healthy vegetation. Especially if there’s a bit of green grass among a stark brown outback landscape. Look for areas where water may have receded over time, like dry river beds, dams, cowls and water run-off paths — it could still be wet under that dry looking surface layer! To really throw a spanner in the works, your typical everyday grass thrives on black soil, and plenty of designated campsites are full of it. It’s great in dry weather, but can be an absolute mission after heavy rain. So, before you drive on wet campsite grass, walk on it and see how squishy it is!   

Put it this way, if you suspect there’s black soil around — avoid it like the plague!


There are hundreds of different kinds of mud conditions out there. Some you can drive over quite easily, others will have you sinking knee-deep before you can say supercalifragilisticexpialidocious! How do you tell the difference? Well, you could try the good old slop test. It’s pretty simple; you either step on the mud or roll your tyre into it and see if it leaves a detailed impression in the ground. If you can see tyre or boot tread imprint in the ground, it means there’s a bit of traction available. If not, good luck! Obviously, this isn’t always 100 per cent accurate, but it’ll give you an idea about what you’re dealing with. 


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