Temperatures across northeastern Ontario have been soaring — prompting the Sudbury and District Health Unit to upgrade its heat advisory to a heat alert.

The alert is in place when the humidex is expected to reach 40C or higher for at least two days.

10 tips for staying healthy in the heat:

  1. Check in at least once a day on family, friends, and neighbours who may have difficulty dealing with the heat. 
  2. Stay cool by wearing light-coloured, loose-fitting, and lightweight clothing. 
  3. Drink lots of water and 100 per cent natural juices, and avoid drinks made with alcohol or caffeine. 
  4. Avoid going out in the sun or heat when possible. 
  5. Slow down and avoid strenuous activity. If you must do strenuous activity, do it during the early morning or late evening hours when it is cooler. 
  6. Keep electric lights off or turned down low. 
  7. Take a cool bath or shower periodically, or cool down with cool, wet towels. 
  8. Take lots of rest breaks, preferably in the shade or in an air-conditioned area such as a library, community centre, shopping mall, or a cooler area of your building. 
  9. Avoid heavy meals and using your oven. 
  10. Place a dish of ice cubes in front of your electric fan. It has a cooling effect.

Source: Sudbury and District Health Unit

The health unit said the city will open cooling centres and extend operating hours at most library branches during the heat wave. The hours of lifeguard supervision at municipal beaches will also be extended.

But those wishing to cool down at the Bell Park Main Beach are out of luck.

The city said that beach is closed until further notice, after a substance was detected in the water.

It said the substance has been traced to a residence where a pool with algae was being drained into a nearby storm sewer.

A bylaw is in place that prohibits the discharge of wastewater from pools into the storm sewer system.

It's unclear at this point whether or not the resident will be fined, the city reported.

Demand 'through the roof'

And there’s some good news for those running air conditioners to keep cool — Greater Sudbury Hydro said it has enough power to meet demand.

But the utility is calling on residents to conserve as much as possible.

A spokesperson for the utility said demand in Sudbury is usually higher in the winter.

"In January, when it's dark for a good chunk of the day and its very cold outside, there's a high demand for hydro electricity," said Wendy Watson.

"But on a day like this, the demand goes through the roof."

Watson says some ways to conserve include keeping unnecessary lights off and turning back your air conditioning when you're not home.

Environment Canada reports weather for the Greater Sudbury region is expected to cool down for the weekend, and rain is forecast for part of Wednesday, Thursday and Friday.