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Heat wave of 2006 derecho series

Series of weather events in Southern Ontario and the United States

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Through Wind, Thunderstorm and North America

Northeastern Ontario derecho (July 17, 2006)

Northern Michigan and Northeastern Ontario

The derecho originated from a severe thunderstorm that was forming across portions of the Upper Peninsula and the northernmost parts of the lower Peninsula of Michigan in the early afternoon hours of July 17. It crossed the North Channel into Northeastern Ontario near Sault Ste. Marie, where it quickly developed into a derecho line. As it crossed Manitoulin Island just southeast of Sault Ste. Marie in Lake Huron, numerous trees were uprooted and some homes sustained heavy damage. An official wind gust of 128 km/h (80 mph) was recorded at the Killarney weather station on the north shore of Lake Huron. Tornado warnings were issued for the area, but damage was consistent with severe straight-line winds.

At about 15:30-16:00 EDT (19:30-20:00 UTC), the storm raced through Sudbury, toppling hydro poles and trees. Highway 69, the major highway linking Sudbury and Toronto, had to be shut down because electrical wires blocked the highway. At that point, the storm system started to take the form of a comma signature of a fast-moving progressive derecho.

At about 17:30 EDT (21:30 UTC), the storm gathered further intensity before striking North Bay, a city of over 50,000, and the surrounding Nipissing District. Numerous trees were uprooted or snapped off and many buildings sustained heavy surface and some structural damage. Just south of the city, radio towers and a lighthouse were demolished by the violent winds. At the nearby Jack Garland Airport, the wind measuring instrument snapped off before the peak gusts could be recorded; some estimates put them higher than 180 km/h (111 mph). Tornado warnings were in effect for the area and several funnels were reported but none has been confirmed. Within the district, the communities of West Nipissing, Callander, East Ferris and Mattawa, all about five hours north of Toronto, declared states of emergency in the wake of the storm as roadways in the area were blocked by felled trees and power was out throughout the region. The town of Mattawa and rural areas in West Nipissing were particularly hard hit as storage siloes were torn apart, roofs were torn from buildings, utility poles were snapped in two and roads were entirely impassable from the debris strewn across them, in some cases for weeks after the storm.

At the same time, the storm affected the Algonquin Park region (mostly the northern portion) and fallen trees killed at least one man from Michigan and injured another, also from Michigan, who were on a canoe trip near Kiosk, a small community located at the northern end of the park.

Ottawa Valley, Eastern Ontario and Southwestern Quebec

Through the next two hours the storm entered the Upper Ottawa Valley affecting places in Renfrew County such as Barry's Bay, Deep River, Cobden, Petawawa and Pembroke. There were numerous reports of damage, particularly blown-off or damaged roofs.

After crossing the Pembroke area, the derecho started to lose some steam. At times, the storm moved at a forward speed of 100–120 km/h (65-75 mph) but had slowed down somewhat when it entered the Pontiac region of western Quebec. Also, the north–south oriented line became more disorganized at its southern end. Still, the storm carried a lot of lightning and damaging wind as it crossed portions of the Outaouais region, the city of Gatineau and extreme northern portions of the city of Ottawa, primarily closer to the Ottawa River, at around 21:00 EDT. Areas such as Chelsea, Cantley, La Peche, Notre-Dame-du-Laus and Kazabazua were hit hard. Spectacular lightning was seen from downtown Ottawa and, when the storm was close enough, some pinkish colour was seen in the northern sky. In the Upper Gatineau north of the National Capital Region, several houses and cottages were damaged and scores of trees were snapped by winds in excess of 90 km/h (55 mph). Five campers were injured by fallen trees, caused by a microburst, while camping in Notre-Dame du Laus. Meanwhile, in the Maniwaki area, a local radio station antenna suffered extensive damage. Northwest of that town in Grand-Remous, several trailers in a park were heavily damaged or destroyed by the force of the winds but no injuries were reported there. Additional damage was reported in the Papineau region further east as well as in Mont-Laurier and the popular tourist village of Mont-Tremblant in the Upper Laurentians. The cities of Ottawa and Gatineau were brushed by the storm but escaped the worst of the effects.

Southern Quebec

During the rest of the late evening, the storm weakened as it travelled through southern Quebec and eastern Ontario, but still brought lightning to the Laurentians north of Montreal. The following day, the remnants of the derecho reformed over parts of New England, including Maine, with effects less severe than the original cluster.

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