The first signs of hypothermia on a hill walk are rarely dramatic. Someone goes quiet, starts lagging behind, gets snappy over nothing, fumbles a zip and trips more than usual. That’s the body cooling, and at this stage it’s usually fixable. Stop, get them warmed up with layers, food and a warm drink, and once they’ve picked up, head down.
The sign that changes everything is when the shivering stops while they’re still cold. That isn’t recovery. It means they’ve run out of the ability to warm themselves, and it’s a 999 call.
We’re going to go through the signs in the order you’ll meet them, including the ones you’ll miss in yourself, then what to do at each end. Hypothermia is far easier to stop early than to treat late, so the early signs are the bit worth learning.
⚠️ A memory aid, not a first aid course. If you spend time in the hills, book a proper two-day outdoor first aid course and keep it in date.
What are the signs of hypothermia?
Medically, hypothermia means your core temperature has dropped below 35°C. On a hill you won’t have a thermometer, and you don’t need one. You judge it by what the person is doing.
Think of it as a slope rather than a switch. At the top you’ve got someone who’s cold, tired and miserable. At the bottom you’ve got someone who can’t stand. Where they are on that slope decides what you do, and the treatment at one end is almost the opposite of the treatment at the other.
Mild hypothermia symptoms: the umbles
The easiest way to remember the early signs is the umbles.
- Grumbles. Unusually snappy, flat or arguing about something that doesn’t matter.
- Mumbles. Speech that’s slurred, slow or vague.
- Fumbles. Can’t manage a zip, a buckle or the wrapper on a chocolate bar.
- Stumbles. Tripping over things they’d normally step over.
- Tumbles. Actually falling over.
Alongside those, you’ll usually see hard shivering, pale or blotchy skin, and someone who’s stopped joining in the conversation and drifted to the back.
The quiet one at the back
Here’s what makes hypothermia so easy to miss. It makes people go quiet before it does anything dramatic. Nobody announces it. They just stop talking, fall back a bit and stop asking for anything.
So watch the quiet one. And watch the fittest, loudest person in the group too, because they’re often the last to admit they’re struggling.
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The signs you’ll miss in yourself
This is the uncomfortable part. Hypothermia affects your judgement, so the person least able to spot it is the person who’s got it.
The signs to catch in yourself are behaviours rather than feelings:
- You’ve stopped bothering to eat, or to put the extra layer on, because it feels like too much faff.
- Your fingers won’t do what you tell them. Map case, zips and gloves become a fight.
- You’ve gone quiet, or you’re irritable with people for no real reason.
- You’re making odd decisions and not noticing. Pushing on when you’d normally turn round, or not checking the map.
None of those feel like an emergency from the inside. That’s exactly why you look for them on purpose, in yourself and in each other.
A simple habit helps. At every stop, glance round the group and ask yourself the umbles question about each person, you included.
When does it stop being mild?
These are the signs that someone has moved from the cold-and-miserable end into serious territory:
- The shivering stops while they’re still cold. This is the big one, and it catches people out because it looks like an improvement. Shivering is the body’s heater. When it stops in someone who’s still cold, the heater has run out.
- Confusion that gets worse. Not making sense, not knowing where they are, or unable to follow a simple instruction.
- They can’t help themselves. Can’t stand, can’t do a zip, can’t hold a cup.
- Drowsiness. Wanting to sleep and hard to rouse.
- Saying they’re too hot. Confusingly, someone badly chilled can feel hot and start taking clothes off.
If you see any of these, call 999 straight away and ask for the police, then Mountain Rescue. If there are two of you or more, one person calls while the others get the casualty out of the wind and off the ground. A seriously hypothermic person needs a hospital, and it will take hours to get them there.
If you haven’t already, register your phone to text 999 before your next walk. It’s for when you can’t get a call through.
What are the stages of hypothermia?
Clinicians split hypothermia into stages by core temperature. Below 35°C is hypothermia, and below 28°C is severe. In between, people get progressively worse.
You’ll never take a core temperature on a hillside, so for walkers the stages come down to two questions:
| Mild end | Serious end | |
|---|---|---|
| Shivering | Shivering hard | Shivering has stopped, but still cold |
| Talking and thinking | Quiet, grumpy, a bit vague | Confused, not making sense, getting worse |
| Hands and feet | Fumbling, stumbling | Can’t stand, can’t hold a cup |
| Awake? | Yes | Drowsy, hard to rouse |
| What you do | Stop, warm them up, then walk down once they pick up | Call 999. They don’t walk anywhere |
If you’re not sure which end they’re at, treat it as the serious end and call.
How to treat hypothermia on the hill
What you do depends completely on which end of the slope they’re on.
At the mild end: warm them up, then get them moving
This surprises people. Once someone with mild hypothermia has been warmed up and can walk, walking off the hill is the best treatment. Working muscles make heat, and they’re a far better heater than anything in your rucksack. Mountaineering Scotland put it the same way in their hypothermia review. Walking off means heading down by the shortest sensible route, not carrying on with the walk.
The order matters. Stop and warm them first:
- Put your own layers on first. The moment the group stops, everyone starts cooling, you included.
- Get out of the wind, behind a wall, a crag or into a group shelter if you carry one.
- Get them sitting on something, not the bare ground, and get more layers on them. If they’re wet and you have shelter, swap wet layers for dry ones.
- Give them something sweet to eat and a warm drink if they’re fully awake and can swallow. Sugar matters here: when you shiver hard, your body burns mostly carbohydrate to do it. Make it something without caffeine, so hot squash rather than coffee or tea, and never alcohol. Alcohol feels warming and actually speeds up heat loss.
- Then, once they’ve picked up, head down by the shortest sensible route.
The thing to watch is whether they improve. If they do, walking off is the plan. If they don’t, or they get worse, you’re at the other end of the slope.
At the serious end: they don’t walk anywhere
Once someone has stopped shivering, is confused or can’t stand, everything reverses. A cold heart is fragile, and rough handling, sitting them up or making them exert themselves can tip it into a fatal rhythm.
The rules while you wait for Mountain Rescue:
- Call 999. Police, then Mountain Rescue. One person calls while the others start on the steps below.
- Handle them like glass. Slowly and gently. Keep them lying flat and don’t let them help.
- Get them off the ground. Mats, empty rucksacks and spare jackets underneath them before anything goes on top.
- Add heat to the middle, never the limbs. Warm water bottles or heat pads on the chest, armpits, neck and groin, always wrapped and never straight on bare skin. Don’t rub their arms and legs.
- Nothing by mouth. Someone who is confused or drowsy can’t swallow safely.
- Seal them in. A survival bag or bivvy bag, then anything windproof, edges tucked underneath, head covered and face clear.
- If they stop breathing, start CPR and keep going. Breathing can be very slow and shallow in a cold casualty, so take up to a minute to check before deciding. A very cold body needs far less oxygen, and people have survived astonishingly long resuscitations. Mountaineering Scotland’s review cites a case where CPR went on for 288 minutes and the patient recovered without lasting cognitive problems. That’s where the saying “not dead until warm and dead” comes from.
Our Emergency Protocol Course takes each of those steps properly, including the wet-clothing decision and why rubbing cold limbs is dangerous.
Can you get hypothermia in summer?
Yes. It doesn’t need snow. Wet clothes and wind pull heat out of you far faster than still, dry air, so a wet, windy day at any time of year can do it, especially once you stop moving.
A common way in is a long stop. Someone turns an ankle, the group waits for help, and nobody’s moving to make heat. On a long wait, the cold can become a bigger problem than the injury.
How do you stop hypothermia before it starts?
Most of this is habit, and none of it is complicated.
- Layer before you’re cold, not after. Put a layer on when you stop, before you feel it. Our guide to the layering system covers what to wear.
- Keep eating. Little and often keeps the heater fuelled.
- Stay dry where you can, and carry a spare warm layer in a dry bag.
- Carry something to sit in. A survival bag or group shelter turns a cold wait into a manageable one. Our hill walking kit list has the rest.
- Check each other. The umbles, at every stop.
- Turn round earlier than you think you need to. As the Lake District rescue teams put it, it is no disgrace to turn back.
Frequently Asked Questions
What are the first signs of hypothermia?
The first signs are usually behaviour rather than anything dramatic. The person goes quiet, lags behind, gets irritable, slurs or slows their speech, fumbles zips and buckles, and stumbles more than usual. Hard shivering and pale skin come with it. The easy way to remember it is the umbles: grumbles, mumbles, fumbles, stumbles and tumbles.
What is the temperature for hypothermia?
Hypothermia is a core body temperature below 35°C, and severe hypothermia is below 28°C. On a hill walk you won’t be able to measure core temperature, so you judge it by how the person is behaving: shivering, speech, coordination and how alert they are.
Should someone with hypothermia keep walking?
If it’s mild, yes, once you’ve stopped and warmed them with layers, food and a warm drink and they’ve picked up. Moving makes heat, and walking slowly off the hill by the shortest sensible route is then the best treatment. But if they’ve stopped shivering while still cold, are confused, can’t stand or are drowsy, they must not walk at all. Keep them lying flat, handle them gently and call 999 for the police, then Mountain Rescue.
Is it good to give someone with hypothermia a hot drink?
Yes, if they’re fully awake and can swallow properly. Warm and sweet is best, because shivering burns mostly carbohydrate. Avoid caffeine, so no coffee or tea, and never give alcohol, which increases heat loss. If there’s any doubt about how alert they are, give nothing by mouth.
Why does shivering stopping mean it’s getting worse?
Shivering is the body heating itself. If someone stops shivering while they’re still cold, their body has lost the ability to make heat, which means they’re getting colder, not recovering. It’s the single most important sign to know, and it means calling 999.
Learn the whole protocol before you need it
Spotting hypothermia early is a skill you can learn in an evening, and the full protocol, from the umbles through to keeping a seriously cold casualty alive while you wait, is in our Emergency Protocol Course. It’s £27, paid once, and £3 of every enrolment goes to mountain rescue services across the UK.
This week, try the umbles check on your walking group at the next stop, quietly, without telling anyone. You’ll be surprised how much you notice. Ask any questions in the comments below.
