Why Hypothermia Catches People Out On British Hills

Hypothermia is not a condition reserved for winter mountaineering on Ben Nevis. It is one of the most common and most underestimated hazards in the UK hills, and it frequently strikes in conditions that feel merely unpleasant rather than dangerous. A wet, windy day at six degrees Celsius in the Lake District or the Brecon Beacons can drain heat from the body faster than a dry, still day at minus five in the Cairngorms.

The reason is simple: wind and wet clothing work together. Rain or sweat soaks your layers, wind strips away the thin layer of warm air next to your skin, and your body loses heat far quicker than it can generate it. Add fatigue, a long ascent, or a stop for lunch in an exposed spot and the balance tips.

The real danger, though, is that hypothermia clouds the one thing you need most: your own judgement. The person who is coldest is usually the last to recognise it, which is why every hillwalker should be able to spot the signs in someone else.

The Early Signs: Grumbles, Mumbles, Fumbles, Stumbles

Early hypothermia is subtle. A casualty at this stage is often still walking, still talking, and still insisting they are fine. Look instead at how they are behaving compared with an hour ago. A handy memory aid is the four "umbles".

• Grumbles — unusual irritability, snapping at companions, or withdrawing from conversation.
• Mumbles — slurred or muddled speech, repeating questions, struggling to find words.
• Fumbles — dropping things, fumbling with a zip, map case or rucksack buckle, clumsiness that was not there earlier.
• Stumbles — poor coordination, tripping over ground they would normally handle easily, a change in walking rhythm.

Alongside these you may notice unusual tiredness, a reluctance to keep moving, or a desire to sit down and rest. Someone may complain of cold hands and feet, or conversely say they feel fine and warm while shivering. That contradiction is a warning in itself. Pale or grey skin, blue lips and a slightly glassy look are further clues.

At this stage the casualty is usually still able to help themselves, which is exactly why you must act now. Waiting another twenty minutes to see if they perk up is how a manageable situation becomes a serious one.

When Shivering Stops: The Serious Stage

Shivering is the body's attempt to generate heat. It is uncomfortable but it is a good sign. When shivering stops in a cold, wet person, treat it as an emergency. The body has run out of energy to keep warming itself and the core temperature is falling.

Look for:

• Confusion, drowsiness, or drifting in and out of awareness
• Slow, shallow breathing and a weak, slow pulse
• Stiff, uncoordinated movements, or an inability to walk
• Cold, pale skin, sometimes with a bluish tinge
• In extreme cases, paradoxical undressing, where the casualty feels overwhelmingly hot and tries to remove clothing

Do not be fooled by a casualty who seems calm and sleepy. Drowsiness in a cold, wet hillwalker is a red flag, not a sign of contentment.

What To Do In The First Fifteen Minutes

Your priorities are shelter, insulation and sugar, in that order.

• Get out of the wind and rain immediately. A rock shelter, a gully, a bothy, an empty building or a group shelter will do. Even a rucksack propped as a windbreak helps.
• Insulate from the ground. More heat is lost downward through wet ground than most people realise. Sit or lie the casualty on rucksacks, foam mats, rope or spare clothing.
• Remove wet clothing and replace it with dry layers. Cut the process short where you can: swap a soaked base layer and add a dry fleece and waterproof shell, plus a hat and gloves. Wrap them in a sleeping bag, bivvy bag or emergency shelter.
• Give sugar and a warm, sweet drink if they are fully alert and able to swallow. Glucose tablets, a handful of jelly babies, a flapjack, or hot sweet tea all work well. Warm sweet liquid helps both hydration and fuel.
• Handle them gently. Rough movement can push cold blood from the limbs back to the core and drop the core temperature further. Keep them still and calm.
• Do not rub the limbs, do not give alcohol, and do not put them in a hot bath or next to a fire. Warm the core gradually instead, using your own body heat, dry insulation and a warm drink.

If the casualty is confused, drowsy or unconscious, place them in the recovery position, keep them insulated, keep monitoring breathing, and call 999 and ask for the police, then mountain rescue. Give a clear grid reference and describe the symptoms you have seen.

Prevention And Looking After Each Other

Most hypothermia is preventable with a little forward planning. Eat and drink regularly rather than waiting for a scheduled lunch stop, because a tired body with low blood sugar chills far faster. Start the day with layers you can add and remove, carry spare dry gloves and a hat, and add a group shelter and a spare insulated layer to your pack even on a summer low-level walk.

Keep an eye on your companions, especially the slowest member of the group, who is often working hardest and getting coldest. The person at the back may also be walking at the pace of the group's weakest member, which means nobody is really watching them.

Finally, be willing to turn back. The hill will still be there next weekend, and a decision made early is far easier than a decision made in a storm with a confused casualty on your hands.