FOCA offers numerous resources on all subjects related to living on the water including:
Winter safety
Boating and Cold Water Immersion

Ice Safety   
Many factors affect ice thickness.  For information on Ice Safety click on this Red Cross link.

Cold Temperatures
From Health Canada:
Extreme Cold 

From the Red Cross website:
Hypothermia and Cold Water from the Red Cross website
Cold Related Emergencies 

Snowmobile Safety  
The OPP remind snowmobilers about the rules governing the operation of a snowmobile.