At a wind chill of −28 °C, exposed skin can freeze in 10 to 30 minutes — and the part that catches people is that you often can't feel it happening. Frostbite and hypothermia both work quietly, and both get handled badly by well-meaning crews trying to help.
The hazard
Cold pulls heat out of you faster than you make it, and wind and wet speed that up a lot. Frostbite freezes skin and the tissue underneath, usually fingers, toes, ears, nose, and cheeks. Hypothermia is your core temperature dropping — and because it goes after judgement early, the person affected is the last one to know. The thermometer alone won't tell you where you stand: wind chill is what decides how fast exposed skin freezes.
What to do
- Work off the wind chill, not the thermometer — and the numbers below are Celsius, same as the forecast. From about −10 to −27 °C there's a real risk of frostbite and hypothermia over a long shift. From −28 to −39 °C the risk is high and exposed skin can freeze in 10 to 30 minutes. Colder than that and it's minutes. Check today's number and set the break schedule from it.
- Warm-up breaks come before you're shivering hard, in somewhere genuinely warm, and get more frequent as the wind chill drops.
- Layer properly: a base that wicks, an insulating middle, a wind- and waterproof shell. Nothing cotton next to the skin.
- Cover the spots that go first — insulated gloves, a neck gaiter, and a winter liner made to work with your hard hat. A toque jammed under the shell changes how the hat sits and how it protects you; use one the helmet manufacturer allows.
- Drink warm fluids through the day. No alcohol — that's a fit-for-work rule and it doesn't move with the weather. It's also a poor way to warm up after the shift: alcohol speeds up how fast you lose heat while making you feel warmer.
- Keep dry spares on site — socks, gloves, a base layer. Wet is what turns a manageable day into a cold injury.
Frostbite: what to do, and what not to
Numbness or tingling, and skin that's gone hard or waxy to the touch, are the signs to work from. There may be a colour change — white, grey, or a difference from the skin around it — but it isn't reliable on every skin tone, so don't wait for it.
- Get them inside and stop the area getting any colder. Cover it loosely, don't rub or massage it, and take off anything wet or constricting.
- Do not try to thaw it out here. Rewarming a frostbitten area on site is not the crew's job — tissue that thaws and then refreezes on the way back out is far worse off than tissue that stayed frozen. Stop the cooling, then get medical care.
Hypothermia: this is an emergency
Slurred speech, stumbling, clumsy hands, confusion, or "I'm fine" when clearly not — treat that as hypothermia and act on it.
- Call 911. Don't wait to see if a coffee sorts it out.
- Handle them gently. No rubbing, no massaging. Let them lie down — no standing them up and walking them around.
- Get them out of the wind, insulated from the ground, and out of wet clothing where you can do it without chilling them further.
- A warm drink only if they're fully conscious and responsive and can swallow properly. Nothing alcoholic, and no smoking.
- Shivering easing off is not improvement. As hypothermia gets worse, shivering weakens and then stops altogether. Someone who's stopped shivering and is still cold and confused is going the wrong way, fast.
Watch out for
- Anyone wet, tired, or hungry — they'll feel it much sooner.
- New crew members. They need time to get used to working in these conditions, and closer supervision while they do — mostly because they don't know our plan yet, not because they freeze faster than anyone else.
- The quiet one. Cold shows up as someone going silent and slow before they'll ever say anything.
Talk it over
- What's the wind chill right now, and does our break schedule actually match it?
- If someone came in with hard, waxy fingers — what do we do, and just as importantly, what do we not do?