I've been told by friends in the US that the first snowfalls have happened and the temperatures have fallen. We haven't had snow here in the UK yet but the first frosts are now behind us and things are starting to feel colder Nick Thomas prepares for his winter fishing.
Winter is nature’s way of saying, "Up yours."
Robert Byrne
Some people stop fishing when the weather turns cold, some people carry on and suffer through winter, some people put on the right gear and catch fish in comfort through till spring. I prefer the latter.
In my youth I did a lot of snow and ice climbing in Scotland and abroad. This was at a time when traditional wool, canvas and duck down mountaineering clothing was being rendered obsolete by a new wave of synthetic fleece, Gore-Tex and other breathable fabrics. Such was vaunted performance of these new fabrics that anyone visiting a climbing shop would be half expecting to hear heavy breathing coming from the racks of anoraks and cagoules. Despite the hype, the improvements in comfort, warmth and weight were fantastic and you didn’t finish a day on the hill looking and feeling like a defrosting ice lolly. Many of those developments in technical fabrics and clothing for climbing have now transitioned into other sports, including fly fishing. One of the leading ice climbers of those times was Yvon Chouinard who developed a new generation of technical axes and crampons for ice climbing and whose company, Patagonia, makes the breathable chest waders I wear today.
One of the basic premises of gearing up for the cold in those days still holds true today; layering. If you read catalogues and websites for outdoor clothing you’ll come across a shed load of different terms for different layers and fabrics and advice on how to combine them into the ‘ultimate technical system for optimum performance’. Or some other marketing speak for ‘you must have this or your mates will look down on you’. When it comes down to it, layering is just about trapping the right amount of the most efficient insulator against heat loss; air. Not too little (you get cold); not too much (you get sweaty and then you get cold).
The human body loses heat through four routes; radiation, convection, evaporation, and conduction. The amount of body heat lost by each of these routes will depend on both your situation and clothing. Let’s deal with each of these in turn.
Conduction is loss of heat by direct contact with a colder object such as the ground or a boat seat if you are sitting down, or a river or lake water if you are wading. Water conducts heat 25 times better than air so wading up to your waist grayling fishing is a pretty poor way of heating water, but a very efficient way of chilling yourself. Preventing heat loss by conduction requires some form of insulating thermal barrier such as neoprene in boots and waders. However bear in mind that if that barrier is impervious then water vapour cannot escape which can then increase conductive heat loss through damp underlying clothing. Damp clothes or socks will also increase heat loss by the next route as evaporative cooling kicks in.
Evaporation is a very efficient way of cooling; it’s the way terracotta wine coolers work. Turning water from liquid to vapour uses a large amount of energy so a small amount of water on any surface dramatically cools that surface as it evaporates. Keeping inner layers of clothing dry, particularly the layer closest to the skin, is one of the most important rules for maintaining an effective insulating clothing system. Keeping penetrating rain or snow out and preventing a build-up of moisture from sweat and condensation are equally important. There’s no point in having the most expensive high-tech rain gear with a cotton T-shirt underneath. There’s a fundamental principle of outdoor survival; cotton kills.
In an average situation the combination of evaporative and conductive heat losses will account for around 20% of heat lost from the body; not the major losses, but ones which can combine with and exacerbate the remaining two routes of loss.
Loss of heat through convection, literally having heat blown away on the breeze, accounts for around 15% of the total loss. That’s what happens when you leave the house door open. Keeping the body warm is the same principle as keeping a house warm; cut out the drafts but allow some ventilation to prevent moisture accumulation. The most effective way to prevent heat loss by convection is to seal yourself in a large plastic bag. That’s not particularly comfortable; believe me I’ve tried it. Crawling into a big orange plastic bivvy bag and sitting on your rucksack is standard mountain survival practice if there’s no other shelter available. It combats conductive and convective heat loss to some degree but moisture soon builds up inside which can start to cool you again. Fishing from inside a plastic bag, or a tent for that matter, isn’t particularly practical for fly fishing, but coarse and sea anglers have been doing it for years. So having a good windproof breathable outer layer is the best solution. Make sure that it fits well to keep drafts out and prevent you pumping warm air out every time you cast. Ideally also make sure that it has enough zips, velcro or other fastenings that you can vent off warm air if you start to get too warm walking along the bank.
There’s one further aspect of convective cooling that we need to consider and which also has a bearing on the amount of heat lost by evaporation and radiation; wind chill. Wind chill is a much misunderstood concept for which there isn’t a standard scientific definition. Simply put it’s the ‘feels-like’ temperature. In still air heat lost from the body warms the boundary layer of air next to the skin which provides some insulation. When the boundary layer is disrupted by a breeze or movement the warmed air is lost and replaced by more lost heat. Think about it like wearing a wet suit in the sea. In a wet suit body heat warms the boundary layer of water trapped next to the skin by the neoprene; take the wet suit off and you are now heating the ocean.
Wind chill does not change the actual temperature; if the still air temperature is 4°C then 4°C of wind chill will not reduce the temperature to freeze water, but it will increase heat loss from the body to that equivalent to 0°C in still air. Wind chill obviously increases with wind speed, but also changes with temperature and humidity; the latter due to the effects of evaporative cooling. Wind chill occurs at any wind speed but becomes very noticeable around 10mph. A 10 mph breeze at 10°C produces a heat loss equivalent loss in still air at 5°C; the same wind at 5°C cools equivalent to -1°C. At 20 mph and 10°C heat loss will be equivalent to 0°C. Above that wind speed the chill factor increases dramatically, but unless you are lucky enough to be fishing in Patagonia, it’s unlikely that you’d be waving a fly rod around in those conditions.
Finally we have heat loss through radiation. This can contribute up to 65% of all lost heat so it’s an important route to account for when dressing for cold weather. An average sized person has a body area of around 2 square metres; about the same as a very large central heating radiator. That’s a big area from which to lose heat. It’s a common misconception that most body heat is lost through the head. In fact the head is about 7% of the body’s surface area and the amount of heat lost is 7-10%. In truth you lose heat equally by radiation from all parts of your body. If the rest of you is warmly wrapped and your head is uncovered you will lose more heat from your head than the rest of you; simply because there’s nothing to stop it radiating away.
This is where layered clothing really comes into play by building up layers of insulating air within and between the sandwiched materials. The ideal situation is to have the most insulation over the greatest skin area on your torso and then less on your legs and arms. This provides the best balance in combatting heat loss and providing the optimum freedom of movement. The Michelin man look is good for warmth, not so good for being able to actually move around, let alone cast easily. Over the years of climbing and fishing I’ve accumulated a large collection of outdoor gear, some of which now stays in the cupboard and other stuff that gets used every day on the water through winter.
Here are three of the essentials of my winter armoury against the cold, all of which are in use on the bank in the photo at the top of this piece. First, a Buff neck tube; these are one of the most versatile bits of outdoor gear you can buy. I’ve had mine for many years and it travels everywhere with me keeping out drafts in winter and insects in the summer. I’ve used it to keep out mosquitoes while photographing grizzlies in Alaska and as a breathing mask against the hordes of midges at Myvatn. It’s a constant companion on the water with multiple uses. On windy days it seals up the gap around my neck without me having to have a jacket collar done up so tight I can’t turn my head to check my back cast isn’t going to attach me to a tree. I can pull it up around my ears if wind chill is nipping and if things get really lively pull it up as a hood over my fishing cap to stop it blowing off. It’s also useful in the summer sprayed with insect repellent or soaked in a stream, wrung out and used as a neck or wrist band to cool down; evaporative cooling being used as a benefit this time.
The second essential for tackling the cold is a good pair of gloves that actually work for fishing. I’ve tried lots; woollen, neoprene, thin leather. All had faults. They either interfered with my rod grip and line handling, got cold when wet or had to be taken off to tie knots and unhook fish. I finally discovered Simms Windstopper half finger gloves which I can wear all day with my fingers free for all the essential tasks of fly fishing. The windproof backs stop wind chill taking all the feeling out of your fingers and the palms and fingers still provide insulation when wet. I’ve been using these for the past few seasons and they really can make the difference between a good day out and packing up because you can’t hold your rod any more.
Finally a more recent addition to the gear collection, an Airflo Thermolite Hoodie. This lightweight jacket provides a tremendous amount of insulation; in fact the first couple of times I wore it I was actually too warm. It comes into its own once the temperature drops below about 5°C and will keep you warm until your fly line freezes in your rod rings and you have to pack up anyway. I’ve also fished in it on cold bright days with heavy rain showers and it shrugged them off and dried in minutes once the sun came out. If it’s really wet then a wading jacket over the top will lock you into a nice warm cocoon from which you can fish all day and grin at the weather and others packing up and going home.
With Christmas approaching you may like to add one or more of these three essentials to your wish list; the hoodie and gloves will set you or your selected gift-giver back around £40, a Buff about half of that. A small price to pay for many days of comfortable fishing in the cold.
A final point; when you are out fishing in winter remember to take breaks for food and drink regularly through the day. Food provides the calories needed to generate heat but you also need to keep hydrated to benefit from eating. Dehydration makes you cold as digesting food is slowed and your blood thickens which inhibits heat transfer to your extremities; a bit like partially draining your central heating system and wondering why it doesn’t work properly. Keep warm and enjoy your fishing through the winter.
Nick Thomas lives in South Wales. He started fly fishing on Scottish hill lochs many years ago and continues to design tie and fish flies for trout, carp, bass and anything else that’s going.