It reached as high as 11.9 kilometres (39,000 feet or 7.4 miles), according to the study, which was published on Nov. 21. Potential warningOther factors included record high temperatures, low humidity and a "near-surface cyclonic wind shear zone," according to the study. A wind shear occurs when the wind speed or direction suddenly changes, so that the wind actually is blowing in two opposite directions. The wind shear near the ground set up the spin that developed the fire tornado plume, Lareau said. "These observations may help forecasters and scientists identify — and potentially warn — for future destructive fire-generated vortices," according to the study.

Source: CBC News December 06, 2018 14:00 UTC