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Ice Safety

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Ice Safety
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
Appearance
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