Fourth of July Blowdown
From BWCAWiki
The Boundary Waters-Canadian Derecho, also commonly called the Boundary Waters Blowdown, was an international derecho that occurred during the afternoon and evening hours of July 4 and the early morning hours of July 5, 1999. It traveled 1300 miles and lasted 22 hours. The Boundary Waters-Canadian Derecho is one of the farthest north "progressive" derechos to have ever been recorded. The derecho caused well over $100 million in damage, killed 4 persons and injured 70. Over 700,000 homes and businesses lost power from the event. Historical records going as far back as Fur Trade era of the 18th century, as well as modern forest surveys have shown no evidence of any previous storm of such force and scale, although much smaller, localized blowdown have occurred.
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Effect on the BWCAW
The storm
The derecho of July 4, 1999, blew down millions of trees within the Boundary Waters Canoe Area Wilderness, most in a line from Ely, Minnesota to the end of the Gunflint Trail. 477,000 acres of wilderness were affected, or a little more than 40% of the total area of the BWCAW. In some areas, such as around Ogishkemuncie and Seagull Lakes, nearly every mature tree was blown down.
Sixty people in the BWCAW were injured during the storm, and one person was killed when the victim drowned.
Wild fire
After the blowdown, the Superior National Forest concluded that the millions of dead trees increased the risk of an uncontrollable "catastrophic" wildfire. The Forest Service has created a plan to minimize this risk by reducing the downed fuels in and around the wilderness. Some areas outside of the wilderness, particularly along the Gunflint Trail, were salvage logged. Within the BWCAW, the Forest Service has begun a series of controlled burns to reduce forest fuels. These prescribed fires, including the Three Mile Island Fire and the South Seagull Fire, are part of a total of 75,000 acres, or about 16% of the blowdown, that will be intentionally burned.
While intentional burns seemingly further damage the forests, the Boundary Waters ecosystem has experienced relatively frequent forest fires for thousands of years, and it is adapted to thrive with such disturbance. For example, Jack pines require the heat of a fire to open their cones and release seeds, and white pines and red pines tolerate low-intensity ground fires that clear out competing vegetation. Unfortunately, high-intensity fires tend to burn any seed left in the soil, and will typically burn any organic matter in the soil itself. Forests that regenerate after such an event tend to be dominated by aspen and paper birch, as the seeds from these species are very lightweight and are transported long distances by the wind. This does not bode well for any return to the pine forests that so many people love and enjoy, at least in much of the blowdown area where fires tend to burn long and hot.
The first major wildfire within the blowdown occurred in August 2005, burning approximately 1400 acres north of Seagull Lake in the northeastern BWCA. The 32,000 acre Cavity Lake Fire burned very hot in the blowdown area in July and August, 2006.
Past events
The July 4, 1999 blowdown was not the first event of its kind in the BWCAW. Smaller blowdowns occured in September of 1992 and July of 1988.
Storm path
North Dakota
In the pre-dawn hours of July 4, a band of thunderstorms developed over far eastern North Dakota. Hector International Airport at Fargo recorded winds in excess of 58 mph (95 km/h) for 40 minutes and a maximum wind gust of 91 mph. Many planes were damaged or overturned. The hangars suffered damage as well.
The storm caused $85 million in damage (1999 dollars) in the Fargo metropolitan area. Over 40,000 people were without power. Cars were overturned and power poles were blown down.
Minnesota
The derecho moved into Minnesota and caused massive damage in Cass, Itasca, and Aitkin Counties. Damage came out to be around $3 million. A semi-trailer truck was blown over on US highway 53 near Canyon, Minnesota.
The derecho felled 600 square miles of forest.
Ontario
The derecho brought more damage when it crossed the border into northwestern Ontario during the early afternoon hours of July 4. At its peak near Thunder Bay, the winds were estimated to have been much stronger, around 100 mph (160 km/h) and it spawned some small tornadoes. One sailboat was overturned and two people were thrown into the cold waters of Lake Superior. They were rescued by a nearby boater.
The storm craved a path of destruction into the sparsely populated forested areas of northern Ontario. The Canadian Pacific track between White River and Chapleau in northestern Ontario was put out of service by fallen trees.
Quebec
As it raced eastward at 62 mph (100 km/h), the system entered into western Quebec in the Témiscamingue region around 11 pm. A gust of 65 mph (102 km/h) was reported at the automatic station of Angliers. There was also a tremendous amount of lightning associated with this derecho, around 6000 lightning strikes per hour. Another person in this derecho was killed at Val-des-Lacs when a tree fell on the victim. A woman was injured when a tree crushed her car.
After narrowly missing the Ottawa area, the storm moved quickly into Montreal around 3 AM heading southeastward toward Maine. Many damages were recorded in the Metropolitan area but the worst affected area of Quebec was further along its path near Sherbrooke in the Eastern Townships where a church was badly damaged, farm buildings were damaged and 2,000 trees were felled. Hydro-Quebec reported that over 600,000 people lost power, some were withour power for over a week in the province of Quebec.
New England
The storm continued southeast and caused more damage in New Hampshire and Vermont, killing one more person, before finally dissipating in Maine after 5 am on July, 5th.
References
- Superior National Forest storm recovery website
- NOAA's Storm Prediction Center page on the BW-C Derecho
Parts of this article are originally from WikipediA, The Free Encyclopedia.
