CALGARY -- Take a look at this chart here: It's high time for the dust-off of @environmentca's heat warning criteria... #abwxpic.twitter.com/Fqk4uWqLAf — Kevin Stanfield (@CTVStanfield) June 1, 2021 Areas in the green (which includes much of southern Alberta and extends up to the Territories) require a 29 C high and 14 C low. Calgary alone will push to that twice; tomorrow, and again Thursday. Our heat warning may come into play this evening. Brooks, Drumheller, Hanna, and many communities farther north – including Edmonton – are already there. The high-pressure wave that's crossing the Rockies is the culprit. While heat is gradually pushing in from the south, the northern expanse of this ridge runs along a band coincident with the northern extent of our warning zone (north of Edmonton). So, heat is pooling there.