In winter, there are a range of dangerous driving conditions, which can quickly manifest and often catch drivers unaware. This is especially so when we get behind the wheel and drive in our warm, comfortable cars. We feel safe and often unaware of what’s going on outside the car. Often we can’t “see” the dangers brought on by adverse weather. This is especially so for ice. It quietly lurks in parts of the road, ready to deal a lethal blow when you don’t expect it.
What is Freezing Fog?
Weren’t we just talking about ice? Freezing fog and ice are very closely related. Freezing fog forms the same way as normal fog. Clear skies cause heat to radiate into space, which leads to cooling at the earth’s surface. This means the air’s ability to hold moisture is reduced, which allows water vapour to condense into small water droplets, which eventually leads to the formation of fog. When fog forms in sub zero temperatures, the water droplets in the air remain as liquid. Essentially they become supercooled. Supercooling is when a liquid is below freezing point but remains as a liquid. This supercooling occurs as liquids need a surface to freeze.
When the droplets come into contact with a surface, they form into feathery ice crystals. This is know as rime. You can easily see this on vertical surfaces, which are exposed to the prevailing wind and also on trees and plans. These ice crystals can also form on other surfaces, including roads and paths.
As a driver you need to be aware that in freezing fog, you could be subject to the terrifying impact of black ice – ice you can’t see.
How to Stay Safe
Staying safe in fog, and freezing fog is mainly about common sense. Following these simple steps can really help.
Reduce your speed – You won’t know where black ice is, so reduce your speed. Exposed areas such as bridges and open roads can ice up quickly. Also pay particular attention to more sheltered areas such as under trees – which can take longer to thaw if subject to ice. Rural areas can get very icy, and are often the last roads to get treated with grit.
By reducing your speed, you are giving your vehicle and yourself more of a chance of dealing with, and possibly recovering from vehicle destabilisation and skidding caused from an encounter with ice. Let’s discuss this more…lets say if one tyre hits a small area of black ice, let’s assume it’s the drivers side (off side) front tyre, when negotiating a left hand corner at 50mph…..
Although you may experience a momentary slip, destabilisation or skid, the remaining available grip from the other three tyres could (and only “could” if you’re lucky) may just be enough to keep your vehicle on it’s intended trajectory to some degree. Possibly your car’s ESP/DSC will do it’s thing and help you out (cut power/apply brakes to different wheels as it deems fit).
But what it can’t do is magic up grip which isn’t there, and it also can’t magically remove the momentum from excessive speed. It can only manage the laws of physics – not defy them!
The faster you go, the more grip will be required to do this should things go wrong.
Check your lights – A lot of cars automatically switch dipped lights on at night or in poor visibility. However, not all cars are that smart and in fog, they don’t always come on – often the driver has no idea of this either, and are driving in bad visibility, with no lights on. If you’re unsure, manually switch your lights on before you start or when you are in fog.
Increase your distance – People, including you and me can’t judge speed that well in fog and freezing fog. Exercise caution and be prepared for mishaps such as vehicles pulling out in front of you at junctions. It’s likely they have failed to judge your distance properly. You too need to be aware of this and take longer to look when crossing traffic. Also drivers tend to “hold on to your taillights” in fog (tailgating) – it’s a physiological “need” to be closer to other drivers in stressful situations, where vision is limited. Be aware of this, chances are they are not being aggressive – just totally unaware of the risks and what they are doing.
Take care of your vehicle – Make sure it’s well services, that the lights work and that the wipers and tyres are all in good condition. Do a POWDER check often:
Petrol – or fuel. Make sure you have enough for your journey and more.
Oil – Check your oil and top up if needed.
Water – Check coolant/antifreeze and also washer fluid.
Damage – If you have any vehicle damage will it be a risk to you or other road users?
Electrics – Are your electrics working? Lights, and indicators for example.
Rubber – Check your tyres for grip, and cuts and bulges to the tyres.
These simple checks and precautions can make all the difference.