Working and playing near bodies of water can be especially hazardous during winter months. Drowning or hypothermia after falling through ice can pose a serious risk to human lives. Click here for more information on ice safety.
Load bearing capacity of ice depends on a number of factors, including:
- Quality of ice
- Thickness of ice
- Ice and air temperature
Look closely before setting foot on or near ice.
- Strong ice: clear blue or blue-black and free of snow, air bubbles, and debris
- Suspect ice: grey in colour, which can indicate the presence of water as a result of thawing (suspect ice cannot bear loads)
- Weak ice: white in colour, brittle texture, and mixed with snow and air bubbles
New ice is usually stronger than old ice, as bonds between the crystals decay with age. For this reason, ice can get more weak throughout the year, even if melting has not occurred.
Thickness
Appearance is a good indicator of quality, but the best way to determine if ice is safe is to cut a hole in the ice and gauge its thickness. Cutting multiple test holes as you move further away from shore will ensure you can be confident in the thickness of the ice. For rivers it is recommended to cut test holes every 50 feet, and every 100 feet for lakes.
NOTE: Information & tables below are intended to act as general guidelines only.
Human Activity:
- Less than 3 inches: avoid ice, it can break under the weight of an average person
- 3-5 inches: able to hold a person, but groups should spread out
- 6-8 inches: minimum thickness for group activities
Moving Loads:
|
Permissible Load
(clear, blue ice) |
Effective Ice Thickness | |
| Lake | River | |
| Passenger Car 2000 kilograms | 7 inches / 18 cm | 8 inches / 21 cm |
| Light truck 2500 kilograms | 8 inches / 21 cm | 9 inches / 23 cm |
| Medium truck 3500 kilograms | 10 inches / 26 cm | 12 inches / 30 cm |
| Heavy truck 7000 to 8000 kilograms | 14 inches / 35 cm | 16 inches / 41 cm |
| 10,000 kilograms | 15 inches / 38 cm | 17 inches / 44 cm |
| 25,000 kilograms | 25 inches / 63 cm | 29 inches / 73 cm |
| 45,000 kilograms | 31 inches / 80 cm | 36 inches / 92 cm |
| 70,000 kilograms | 39 inches / 100 cm | 45 inches / 115 cm |
| 110,000 kilograms | 49 inches / 125 cm | 57 inches / 144 cm |
Stationary Loads:
|
Permissible Load
(clear, blue ice) |
Effective Ice Thickness | |
| Lake | River | |
| 1,000 kilograms | 8 inches / 20 cm | 9 inches / 23 cm |
| 2,000 kilograms | 12 inches / 30 cm | 14 inches / 35 cm |
| 4,000 kilograms | 18 inches / 45 cm | 20 inches / 52 cm |
| 8,000 kilograms | 24 inches / 60 cm | 27 inches / 69 cm |
| 25,000 kilograms | 43 inches / 110 cm | 50 inches / 127 cm |
| 45,000 kilograms | 59 inches / 150 cm | 68 inches / 173 cm |
| 70,000 kilograms | 71 inches / 180 cm | 82 inches / 207 cm |
| 110,000 kilograms | 91 inches / 230 cm | 104 inches / 265 cm |
Basic Ice Safety Practices
- Never go alone or attempt to rescue a victim of ice failure alone
- Stay away from cracks, seams, pressure ridges, slushy areas and darker areas that signify thinner ice
- Listen for loud cracks or booms coming from the ice and know what they indicate
- Always wear a life jacket or personal flotation device (PFD) over an ordinary snowmobile suit or layered winter clothing
- Never wear a life jacket when traveling across ice in an enclosed vehicle as it can hamper escape in case of a breakthrough
