Canyons are usually dark places, and because of the lack of sun, cold places. The water temperature in canyons near Sydney is usually around 10-14 deg C in summer, and a few degrees less in winter. At these temperatures, particularly in water, hypothermia can set in quite quickly unless precautions are taken. There are lots of ways of staying warm in a canyon, and this article will discuss some of them.
Drysuit, wetsuit or no suit?
Drysuits are often used in canyons in North America. A drysuit is just as its name suggests - a suit that stops you from getting wet. They are a full body suit made of a waterproof material, and work by having tight seals around the hands, feet and neck or head that prevent water from entering. As the main loss of heat is from the circulation of cold water against the skin, they are very effective at keeping you warm in extreme conditions. However, they are prone to puncture, and once punctured are worse than useless. As most local canyons have a lot of sharp sticks and branches hidden underwater, puncture is particularly likely, and for this reason they are not used. They are also very expensive.
Wetsuits are the most common way of staying warm in canyons all around the world. Wetsuits work by having a layer of neoprene next to your skin, which traps water. This water is warmed by your body, and acts as an insulating layer against the colder water outside.
Wetsuits come in a variety of shapes and sizes. Steamers have long arms and long legs, spring suits have short arms and short legs, bib and braces style wetsuits are in two parts with a set of overalls, and a jacket that goes over the top providing extra warmth for the torso.
The most important thing for a wetsuit is to fit. A wetsuit that fits is tight, particularly in the torso area. As mentioned above, it works by trapping a warm layer of water in the neoprene against your skin. If there is a gap between the wetsuit and your skin, the cold water can circulate in this gap, and carry away the body's warmth.
There are a couple of major disadvantages of wetsuits. One is that they are heavy, particularly when wet, and can take up considerable space in your pack. The other is that once you are wet in a wetsuit, cold air can in fact accelerate your cooling by blowing over and through the wetsuit.
No suit can sometimes be warmer than a wetsuit. Most canyons near Sydney have only one or two short swims, or deep wades. In some cases even these can be avoided by judicious bridging or climbing. If not, by taking your top off, swimming or wading the pool, and then putting a thermal top on, you keep your torso relatively dry and avoid having cold clothing against your skin.
More frequent swims can be tackled using this method as long as:
- the air temperature is not too cold
- your party size is small and your party is efficient and keeps moving
- the swims are short
It can be a bit tougher for females, as they generally have a bikini top or sports bra to contend with that doesn't dry as quickly!
I have only used a wetsuit on about 10 of the last 60 canyons I have visited. Of the times I didn't use a wetsuit, I was only particularly cold twice. Those two times we had party sizes of 13 and 9 respectively, and as a result were unable to keep moving.
Other useful techniques
- For canyons where there is a lot of swimming, floating on a lilo (inflatable air mattress) may be an option. This keeps most of your body out of water. However, only a few canyons near Sydney are suitable for this.
- For canyons with less swimming, make sure your pack has flotation in it (dry bag or inflatable wine bladder). If you are swimming on your back, with your pack on your back and the waist strap done up, the flotation will keep much of the front of your torso out of the water.
- Wear a beanie. A significant amount of heat is lost through your head, particularly if the rest of your body is well covered. A beanie can make a huge difference. Avoid getting it wet, as cold air subsequently flowing over it then creates an evaporative cooling effect that outweighs the beanie's warming properties.
- If you are wearing a wetsuit, you can wear a waterproof spray jacket over the top in between swimming sections. This can prevent the cooling effect of air flowing around and through the wetsuit.
- If your wetsuit is a bit loose (or even if it is not loose, but you just want some extra warmth) you can wear a set of thermals underneath. This can be particularly useful for spring suits, where there is no protection for arms or legs.
In the end, the decision to take a wetsuit or not is up to you. If you are just starting out, I would suggest that you use a wetsuit, unless you know that the swimming/wading is going to be very limited.
Once you have done a reasonable number of canyons, you will have a better feel for how well your body tolerates the cold. Based on your party's size, experience and the canyon you are visiting, you can make the decision about whether to take your wetsuit.
A final word of warning. Canyon conditions change. What might have been a shallow wade last time, or in the guide book, might now be a swim. If this is a problem for you, then you should probably take a wetsuit! However, it is rare in Sydney canyons for major changes to occur - for instance a few short wades is unlikely to become a number of long swims.