Environment Canada has issued a flash freeze warning for the Nipissing and Sudbury Districts.
The warning applies to North Bay, West Nipissing, Powassan, Mattawa, French River and the Greater Sudbury region.
A flash freeze occurs when water freezes in a very short period of time as a sudden drop in temperature occurs.
Environment Canada says people in the flash freeze zone should look for adverse weather conditions and take necessary safety precautions.