Lesson 1: How the cold affects you
Your body is always making heat and losing it. In winter, you lose heat faster than you make it. Heat leaves through exposed skin, through contact with cold or wet surfaces, through wind blowing past your body, and through sweat and breath.
- Wind carries heat away faster, even at the same air temperature.
- Wet clothing pulls heat from your body much faster than dry clothing.
- Sweat soaks your layers and leaves you colder when you stop moving.
What raises your risk
- Being tired, such as late in a long night shift.
- Alcohol, smoking and some medications.
- A past cold injury, or conditions that affect blood flow.
- Not eating or drinking enough.
Cold also slows your hands and your thinking. Guards make more mistakes and have more accidents when they are very cold.
Lesson 2: Reading the wind chill
Wind chill describes how cold it feels on your skin when the wind blows. It is not something a thermometer can measure, and it does not make objects colder than the air. Check the forecast before every outdoor shift.
| Wind chill | Risk | Exposed skin can freeze in |
|---|---|---|
| 0 to -9 | Low | Not a main concern |
| -10 to -27 | Moderate | Risk with long exposure and poor protection |
| -28 to -39 | High | 10 to 30 minutes |
| -40 to -47 | Very high | 5 to 10 minutes |
| -48 to -54 | Severe | 2 to 5 minutes |
| -55 or colder | Extreme | Less than 2 minutes; outdoor conditions are hazardous |
In steady winds over 50 km/h, frostbite can happen even faster than the chart shows. At high risk and above, check your face, ears, fingers and toes often for numbness or whiteness, and limit your time outside.
Lesson 3: Dressing and pacing your work
Layer up
| Layer | Job | Good materials |
|---|---|---|
| Inner | Moves sweat away from skin | Wool, polyester, polypropylene |
| Middle | Keeps heat in | Fleece, wool, insulated jacket |
| Outer | Blocks wind and water | Windproof, waterproof shell |
- Avoid cotton next to the skin; it stays damp.
- Cover your head, ears and face, and wear mitts or gloves suited to the task.
- Wear insulated, waterproof boots with socks that are not so thick they squeeze your feet.
- Open zippers or remove a layer before you start to sweat, and add it back when you stop.
- Change into dry clothes as soon as you can if you get wet.
Warm-up breaks, food and drink
Take regular breaks in a heated space, and go in right away if you notice signs of cold stress. Drink fluids often; warm, sweet, non-alcoholic drinks or soup are good choices. Limit caffeine and avoid alcohol: alcohol makes you feel warm when you are not. Eat regular meals, because your body burns more energy in the cold. Watch out for coworkers, and use your check-ins.
Lesson 4: Frostbite and hypothermia
Frostnip and frostbite
Frostnip is mild: the skin looks white or yellowish but stays soft, and colour comes back as it warms. Frostbite is more serious: skin becomes hard, numb and discoloured, blisters may form and damage can be permanent. Hands, feet, nose and ears are most at risk.
- Move the person somewhere warm.
- Warm the area gradually with body heat, blankets, or water just above body temperature.
- Do not rub, massage or shake the skin.
- Get medical help right away for severe frostbite.
Hypothermia
| Stage | Signs | Action |
|---|---|---|
| 1 (mild) | Shivering, goosebumps, numb hands, tiredness | Get to shelter, keep moving, dry and warm up gradually |
| 2 (moderate) | Strong shivering, clumsy movement, mild confusion, blue lips | Call 911; warm gradually while you wait |
| 3 (severe) | Shivering stops; trouble speaking, thinking and walking | Call 911; handle the person gently |
A quick check: can the person touch their thumb to their little finger? If not, hypothermia may be getting worse. Do not try to stop shivering; it helps warm the body.
Lesson 5: Ice, snow and winter driving
On foot
- Take short steps, keep your feet flat and walk slowly.
- Keep your hands out of your pockets so you can catch your balance.
- Use handrails, and hold the door frame when getting in and out of a vehicle.
- Report icy entrances and blocked exits.
Driving
- Winter tires grip better once temperatures drop below 7°C.
- Keep windows and mirrors clear before you drive.
- Black ice forms first on bridges, overpasses and shaded spots. Dark, shiny pavement is a warning sign.
- In a skid, ease off the gas or brake and steer where you want to go.
- Do not use cruise control on snowy or slippery roads.
Winter site checks
- Make sure fire exits and the paths outside them are clear of snow and ice.
- Check that fire hydrants and fire department connections are not buried.
- Watch for icicles and snow hanging over doorways and walkways, and keep people away from them.
- Record and report every hazard you find, with the time and location.
If you are stranded
- Stay with your vehicle and call dispatch.
- Turn on your flashers.
- Open a window slightly for fresh air.
- Run the engine only now and then for heat, and keep the exhaust pipe clear of snow.
Vehicle exhaust contains carbon monoxide, which can build up to dangerous levels in garages, sheds and other closed spaces. Never warm up a patrol vehicle inside a closed garage. Keep a winter kit with warm clothing, a blanket, a flashlight, a shovel and energy food.
Sources
- Government of Canada: Wind chill and the Wind Chill Index
- Health Canada: Extreme cold
- CCOHS: Cold Environments - Working in the Cold
- CCOHS: Cold Environments - General
- Ontario: Official MTO Driver's Handbook, Driving at night and in bad weather
- Transport Canada: Winter driving
- Health Canada: Keep carbon monoxide out of your home