No tornado in Ottawa on Saturday, researchers say

Researchers with Western University's Northern Tornadoes Project say an intense downburst with winds peaking at 190 km/h hit southern Ottawa on Saturday, not a tornado.

Their work to determine whether any tornadoes occurred continues to the east of the capital in the Clarence-Rockland, Ont., area.

The intense wind and thunderstormknown as a derechokilled 10 people and knocked out power to hundreds of thousands more.

About 115,000 customers in the wider Ottawa-Gatineau region were without power as of about6 a.m. Wednesday, and all the cleanup is expected to take weeks.

'Particularly intense downburst' to blame for south Ottawa damage

The university'sresearch team visitedsome of the hardest-hit areas, including Ottawa, andconfirmed Tuesday that Uxbridge, Ont., northeast of Toronto,was hit by a tornadowith winds peaking at 195 km/h.

It doesn't appear that any tornado hit the parts of southern Ottawa the teamexamined.

"Analysis of the data reveals that a particularly intense downburst, not a tornado, was responsible for the damage there, with maximum wind speeds reaching 190 km/h," the researcherstweeted Wednesday.

"Intermittent intense damage along a path [about] 5 km wide continues ENE at least as far as Plantagenet. Additional details on that damage will be forthcoming."

A downburstis cool air suddenly dropping from the unstable air masses involved in thunderstorms.

The United Nations climate change panel has warned that humans warming the planet will likely cause more intense storms in North America. Hydro Ottawa hasreportedstronger winds more often in recent years.

A weak landspout tornado hit an area east of Ottawa near Casselman, Ont., less than a week before the derecho. Ottawa also broke daily heat and rain records going back to the 1870sthe week before.