A heat warning, initially issued on Monday, has been expanded to include the East Kootenay.
According to Environment Canada officials, daytime high temperatures are expected to range between 35 and 40 degrees Celsius across much of B.C.
Overnight lows will be offering little relief, with temperatures dipping between 18 and 20 degrees in the early mornings.
Temperatures are expected to top out at 36 degrees in the Cranbrook and Invermere areas on Thursday and linger in the mid-30s for most of the week.
The high temperatures are expected to last from Tuesday to Saturday, with the hottest days coming later this week.
“The peak daytime high temperatures are expected from Wednesday to Friday. Then, a slow cooling trend is likely next weekend to early August,” said Environment Canada officials. “The hottest time of the day will be late afternoon to early evening. The coolest time of the day will be near the sunrise.”
The heat is expected to ease off slightly by the weekend, with a high of 30 degrees predicted for Sunday.
Experts are warning you to be on the lookout for signs of heat-related illnesses, such as swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions.
Young children, pregnant people, older adults, people with chronic illnesses and people working or exercising outdoors are especially vulnerable to exposure from high temperatures.
More: Environment Canada weather alerts