Tornado warnings have been issued for cottage country as hot and humid conditions continue to grip much of central and southern Ontario.

Environment Canada issued tornado warnings Tuesday for Haliburton, Peterborough, Orangeville and the Waterloo area.

A funnel cloud has been spotted in the Orangeville region.

Severe thunderstorm warnings have also been issued for the Huntsville, Parry Sound and Muskoka areas, while much of southern Ontario remains under a thunderstorm watch.

Environment Canada's weather office website says "This is a warning that severe thunderstorms with tornadoes are imminent or occurring in these regions. Monitor weather conditions. Take immediate safety precautions."

Forecasters warn thunderstorms developing over the areas could bring violent weather conditions similar to those experienced on Monday night.

More than 4,000 homes were without power Monday as torrential rain, damaging winds and hail battered power lines in Huntsville and Parry Sound.

Boiling temperatures, a smog advisory and humid conditions have raised the new Air Quality Health Index to seven or high risk.

Children, the elderly and people with heart or breathing problems should reduce or reschedule physical exertion outdoors to periods when the index is lower, especially if they experience symptoms.

Officials say residents should also avoid consuming alcoholic drinks, caffeine and sugar.

Consumers are being asked to limit the use of dishwashers, washers and dryers and and to turn off non-essential lights.

Air conditioners should be set to 26 degrees or higher and curtains and blinds should be closed to keep out the sun.

Toronto Hydro recommends:

  • Using fans instead of air conditioners;
  • Using a clothesline to dry clothing;
  • Setting pool heater thermostats back one degree;
  • Washing laundry in cold water; and
  • Unplugging secondary fridges.

With a report from CTV's John Musselman