Ice is the North’s great road system and its most patient trap. The skill isn’t bravery in either direction — it’s reading: knowing what this particular ice, in this spot, on this day, will bear.
Colour is the first word
- Clear blue-black ice is the strong stuff — frozen solid and dense, the benchmark all thickness guidance assumes.
- White or opaque ice froze with snow or air mixed in. Figure it at half strength and demand double the thickness.
- Grey ice is water. Grey means saturation, rot, or recent overflow. It gets no thickness allowance; it gets avoided.
The numbers (for clear, new ice)
The widely used minimums: 10 cm (4 in) for a person on foot, 12–18 cm for a snowmachine, 20–30 cm and up before anyone talks about vehicles. These are minimums for good ice — white ice doubles them, and moving water voids them entirely. Check with a spud bar or auger every couple hundred metres, and more often when anything about the surface changes.
Where ice lies
Thickness is local. The same lake that carries a truck in one bay will drown a walker fifty metres away. Chronic thin spots:
- Inlets, outlets, and narrows — moving water erodes ice from below
- Over springs and reefs — upwelling keeps ice thin all winter with no surface warning
- Around points where current squeezes
- Under snowdrifts — snow insulates; the blanket that keeps you warm keeps the ice thin
- Pressure ridges and cracks — jumbled, refrozen, unpredictable; cross at known good spots or not at all
- Early and late season everywhere: freeze-up and break-up ice changes by the hour, and afternoon sun rots what morning cold made
Local knowledge outranks every rule here. The person who’s crossed that narrows for thirty winters knows where the spring is. Ask.
Dress for the swim you don’t plan
On questionable ice: ice picks around your neck (bare hands cannot grip wet ice — this is the difference between a story and a statistic), pack worn loose on one shoulder, and space between travellers so one hole gets one person. A rope and a throw-bag ride in the group, not at the bottom of a sled bag.
What happens if the ice loses the argument anyway is the next leg: Through the Ice.
Field checkpoints
- Can you rank blue-black, white, and grey ice — and say what each demands?
- Can you name five places on a lake where ice runs thin?
- Are your picks on your body, not in your pack?