Hypothermia: Recognising It Before It’s Dangerous
The thing that makes hypothermia dangerous in Australia is that nobody expects it. It is filed mentally under snow and mountaineering, when the actual Australian version is a wet walk in the Blue Mountains in October at 12°C with a breeze.
Wet clothing conducts heat away roughly twenty times faster than dry, and wind multiplies that again. You do not need to be cold-looking to be cooling, and — this is the important part — judgement degrades before the obvious signs appear. The person who insists they are fine and wants to push on to the next ridge is often the person who is already impaired.
The emergency numbers in this guide are Australian. If you are somewhere else, call your own country’s emergency number instead — 911 in the United States and Canada, 999 in the United Kingdom, 112 across Europe and on most mobile phones worldwide. The advice itself applies wherever you are.
The 10-minute version
- Wet plus wind plus 10–12°C is a hypothermia scenario. No snow required.
- The first sign is behaviour, not temperature — clumsiness, mumbling, stumbling, poor decisions, irritability. Watch other people, because you will not notice it in yourself.
- Insulate from the ground, get them dry, and add warmth gently. Rough handling and rapid rewarming of a severely cold person can cause cardiac arrest.
The stages, by what you can see
| Stage | What you see | What to do |
|---|---|---|
| Mild | Shivering, cold hands and feet, still alert and coordinated | Shelter, dry clothing, insulation from the ground, warm sweet drinks, food, gentle movement |
| Moderate | Violent shivering slowing or stopping, clumsiness, slurred or mumbled speech, confusion, apathy, stumbling | Stop moving them around. Shelter, insulate, cover the head, no alcohol, no vigorous rubbing. Call for help |
| Severe | Shivering has stopped, muscles rigid, barely responsive or unconscious, slow weak breathing and pulse | Emergency. Call 000. Handle extremely gently, insulate thoroughly, do not attempt active rewarming of the limbs |
The counterintuitive one: when shivering stops, that is worse, not better. Shivering is heat production. Its absence in a cold person means the body has run out of capacity.
Treatment, in order
- Get them out of the wind and wet. Any shelter — a tent, a car, a hollow, behind a rock. See Shelter.
- Insulate from the ground first. The ground steals heat faster than the air, and a person lying on cold earth is still cooling regardless of how many jackets are on top.
- Remove wet clothing if you have dry replacements. If you do not, wring it out and insulate over the top — wet wool still insulates somewhat, wet cotton does not.
- Cover the head and neck. Significant heat is lost there and it is cheap to fix.
- Add gentle heat to the core, not the limbs: a warm (not hot) drink if they are fully alert, another person’s body heat, chemical heat packs wrapped in cloth on the chest and armpits.
- Food, if they are alert. Shivering burns fuel and an empty person cannot generate heat.
- Keep them horizontal and handle them gently in moderate or severe cases.
The rewarming errors
These are the ones that cause harm.
- No alcohol. It dilates surface blood vessels, dumps core heat to the skin, and feels warming while making things worse.
- No vigorous rubbing of cold limbs.
- No hot baths or direct high heat for a moderately or severely hypothermic person. Rapid rewarming of cold peripheries pushes cold blood back to the core and can trigger a fatal arrhythmia.
- No standing them up and walking them out if they are past mild. Movement circulates cold blood from the limbs.
- Do not assume shivering means they are fine, and do not assume its absence means they have warmed up.
- Do not stop resuscitating early. In severe hypothermia a person can appear dead and still be viable — hence the emergency medicine adage that nobody is dead until they are warm and dead. If they are unresponsive and not breathing normally, start CPR and keep going.
Why judgement goes first
The practical implication of hypothermia impairing cognition is that the affected person is the least reliable judge of their condition. They will say they are fine, refuse to stop, and make progressively worse decisions about route, pace and turning back.
Which means the actual skill is watching other people:
- Are they stumbling, or dropping things?
- Is their speech slower or mumbling?
- Have they stopped talking, or stopped complaining?
- Are they doing something obviously unwise — taking off a layer, sitting down, wandering?
Any of those in cold, wet conditions means stop now and treat, regardless of what they say. Turning around early is the decision, and it has to be made by whoever is still thinking clearly.
What actually goes wrong
Nobody expects hypothermia in Australia, so nobody looks for it.
Cotton. Jeans and cotton t-shirts in wet weather are the classic Australian hypothermia outfit.
The group pushes on because the affected person says they are fine.
Treatment happens on the ground with no insulation underneath.
Alcohol is offered as a warming measure.
The limbs are rubbed vigorously or plunged in hot water.
Rain gear is in the pack and never put on until people are already wet — put it on before you are cold and wet, not after.
Nobody has spare dry layers, so wet clothing stays on.
Thresholds
| Situation | The rule |
|---|---|
| Wet, windy, under about 12°C | Assume hypothermia is possible. Watch everyone |
| Any stumbling, mumbling or poor decisions | Stop and treat, whatever they say |
| Shivering stops in a cold person | Deteriorating. Escalate and call for help |
| Moderate or severe | Handle gently, keep horizontal, no walking, no hot water, no alcohol |
| Unresponsive, not breathing normally | Start CPR and continue. Cold does not mean unsalvageable |
| Treatment position | Insulated from the ground, out of wind, head covered |
| Fluids and food | Only if fully alert |
What it costs
| Tier | Spend | What it buys |
|---|---|---|
| Free | $0 | Knowing the wet-and-12°C rule, watching others for behaviour change, insulating from the ground, turning back early |
| Solid | ~$60–120 | A proper rain shell, a wool or synthetic thermal layer, a beanie, a space blanket, a closed-cell foam sit pad |
| Better | ~$200–400 | A bivvy bag or emergency shelter for the group, chemical heat packs, a warm insulating layer that works damp |
| Never | $0 | Cotton, as your walking layer, in cold wet country |
The drill: the pack check
Before any cold-weather or wet-weather walk, two minutes.
- Rain shell, actually waterproof, in the pack.
- One warm layer that works wet — wool or synthetic, not cotton or down.
- A beanie and gloves. Cheap, tiny, disproportionately effective.
- A space blanket and a sit pad. Together under 300 grams and they solve ground insulation and wind.
- Spare dry socks and a dry base layer in a dry bag.
- Say the rule out loud to the group: if anyone starts stumbling or mumbling, we stop and shelter, no debate.
Frequently asked questions
Can you get hypothermia in Australia without snow?
Yes, routinely. Wet clothing plus wind at around 10–12°C is enough, and it happens on ordinary bushwalks in temperate areas. Wet clothing conducts heat away far faster than dry.
What are the first signs of hypothermia?
Behavioural: clumsiness, dropping things, slurred or mumbled speech, apathy, irritability and poor decisions — usually before the person looks unwell. Shivering is present early and stops as it worsens.
Why is it bad when shivering stops?
Shivering generates heat. If a cold person stops shivering, the body has run out of capacity to warm itself, which means they are deteriorating rather than recovering.
How do you treat hypothermia?
Shelter from wind and wet, insulate from the ground, replace wet clothing with dry if available, cover the head, and add gentle warmth to the core — a warm drink if fully alert, body heat, or heat packs wrapped in cloth on the chest. Handle gently and keep them horizontal in moderate or severe cases.
What should I never do?
No alcohol, no vigorous rubbing of limbs, no hot baths or direct high heat for a moderately or severely affected person, and no walking them out. Rapid rewarming of cold limbs can trigger a fatal heart rhythm.
What if they are unresponsive and not breathing?
Call 000 and start CPR, and keep going. Severe hypothermia can mimic death, and people have been resuscitated after prolonged cold — the principle is that nobody is dead until they are warm and dead.