Rule of Threes and survival priorities if you become lost

In a survival situation, the rule of threes involves the priorities in order to survive. The rule allows you to effectively prepare for emergencies and determine decision-making in case of injury or danger posed by the environment.

What is the rule of threes?

Generally, the rule of threes contains the following:

  • You can survive for 3 Minutes without air (oxygen) or in icy water
  • You can survive for 3 Hours without shelter in a harsh environment (unless in icy water)
  • You can survive for 3 Days without water (if sheltered from a harsh environment)
  • You can survive for 3 Weeks without food (if you have water and shelter)

The main point of the Rule of three is that we have to focus on the most immediate problem first. If the weather is warm, you will need to focus on finding water as your priority, food and shelter building can wait. There is no need to think about food or water if you are cold and wet as hypothermia presents the greatest threat to your survival. Make no mistake, if you are shivering and can’t get dry and warm, you may not able to function after three hours. If you are alone, you may have only about three hours to live.

The rule may be useful in determining the order of priority when in a life-threatening situation, and is a generalisation (or rule of thumb) rather than being scientifically accurate.

Top 7 survival priorities

If you ever find yourself in a wilderness survival situation you must think carefully and prioritise your actions. Water, warmth, signals, shelter and food are the commonly known top 5 priorities in a survival situation. I also like to add positive mental attitude and first aid to these priorities. First aid will not always be required, but when you or a member of your group are injured, attending to this should be your first priority.

Typically, your survival priorities will be in the following order. However, the nature of each survival situation ultimately dictate the final order.

  1. Positive Attitude
  2. First Aid
  3. Shelter
  4. Water
  5. Warmth
  6. Signals
  7. Food

1. Positive Attitude

Survival is a state of mind. Control your fears and avoid panic. It only takes 3 seconds to make a poor decision, so stay calm, relax and assess your situation. You can effectively plan a course of action only after considering the aspects of your situation. Remaining calm with a positive state of mind is the key to survival in an outdoor emergency.

2. First Aid

If you or a member of your hiking group are injured, this will be your first priority. Administering first aid to yourself or others to address Airway, Breathing, Circulation, or Deadly Bleeding should always be a priority as long as there is no other immediate danger like a fire.

I highly recommend having wilderness first aid knowledge and training, but common sense can also help you discern between urgent issues and stable, minor issues.

3. Shelter

In extremely cold temperatures, and in wet and cold conditions taking shelter from the wind, precipitation and the ground is extremely important. You need to keep your body warm so the risk of hypothermia is reduced. In extremely hot temperatures taking shelter from the sun is a priority.

Your body looses and gains heat through radiation (sun, fire, body), convection (hot and cold wind), sweat (heat loss through evaporation), conduction (sleeping on snow), breathing (heat loss), and drinking (heat gain/loss).

4. Water

Water is your most valuable commodity.It is used by most processes of the human body, so naturally it’s one of our most important needs. Always treat suspect water, but remember, drinking dirty water is better than dying of dehydration. Stay away from water with obvious signs of toxicity like dead animals and no vegetation. Common sense should be your guide here. Your need for water will vary depending on how hot and humid the environment is and your activity levels.

If the heat is extreme, rest during the day and consider night travel. Don’t exert yourself if you are dehydrated, and be aware that dehydration can prevent you from thinking clearly.

In cool climates, drinking water is equally  important. You want your body to perform, and being dehydrated hinders your ability to maintain your temperature. Don’t eat snow (it will cool you down) if you can melt snow with fire and a sock. If you can’t melt snow, then eat snow as a last resort.

5. Warmth

Fires are really important. They keep you warm, dry out wet clothes, purify water, melt snow for water, produce light, signal rescuers, heat food or drinks (which helps keep you warm), and they will boost morale. Keeping a positive mental attitude is important and a fire really helps. The list of benefits fire provides in a survival situation is literally endless.

Clothing and fire are effective ways of maintaining your body temperature. If this is not enough, find or build a shelter to minimise heat loss or gain. Your survival kit should have multiple tools for starting a fire.

The ability to make fire in varied conditions with varied tools is a critical survival skill and one that involves practice, trial, error, failure and patience.  From natural materials to modern tools, it is wise to be knowledgeable in a variety of fire starting methods.

6. Signals

Signalling is not as urgent as first aid or shelter, but you should always be ready to signal for help as quickly as possible. You never know when the next opportunity to signal someone could present itself. Try to find high ground to send an emergency text if there are cellphone towers nearby. Signal fires, signal mirrors, whistles and plbs should be used when appropriate. A pack cover tied to a tree, your backpack left in an open area, a large signal on the ground made from branches, anything that attracts attention will improve your chances of being found.

Use a whistle and signal in blasts of three. Don’t yell for help. Yelling doesn’t carry far and can expend a lot of energy. A mirror or other object that reflects the sun can make you visible to a helicopter or plane. If there is no chance that anyone will come looking for you then you need to make a plan to walk out on your own.

7. Food

Our bodies are naturally prepared for short periods of starvation, that’s why they tend to accumulate fat. Few short term survival situations require food. When lost in the bush, most people panic through fear they will run out of food. If you are lost in a remote location with no prospects of being found in the next weeks or months then food will be a priority. For most short-term survival situations, food acquisition is not necessary.

Conserve calories: do things the easiest and most efficient way. Don’t fight nature, work with it.

Ration your food, but keep in mind, food is the least important wilderness survival priority. Your body will be consuming itself anyway, and it’s not likely your calorie intake will outweigh your output so its no point wasting energy trying to find food. Try and conserve your body’s energy reserves. Staying put, building a shelter, finding water and signalling for help or self-rescuing are your best options.

Use these rules as a guide

The Survival Rule of Threes and Seven Survival Priorities should be used as a guide to create the best opportunities for survival. The survival rule of threes is a great rule to rely on when you need to make a split-second decision in an emergency. It is also a good rule of thumb to recall when when planning your hikes and building your survival kits. Use common sense and act according to your unique circumstances and needs.


  1.  Colin Towell (2011). Essential Survival Skills. Penguin. ISBN 978-0-7566-7338-3.
  2. “Wilderness Survival Rules of 3 – Air, Shelter, Water & Food”.

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