Southern Great Lakes Derecho of 1998

It has been suggested that this article or section be merged with Spencer, South Dakota tornado and Mechanicville Tornado Outbreak (Discuss)

The Southern Great Lakes Derecho of 1998 was a derecho event that occurred on the final weekend of May, May 30 and 31, 1998. While racing from southern Minnesota to New York in 15 hours, this derecho killed 6 people and injured over 200. Over 2 million customers lost power. Some had to go without power for up to 10 days.

Synopsis

This derecho got its start from a developing low pressure system that moved into the northern Great Plains and Great Lakes. The derecho formed from the same storm system that spawned the Spencer, SD Tornado, which killed six people. The supercell thunderstorm which produced that tornado transitioned into the derecho which killed another six people.

Late in the evening on the May 30, the tornado-producing supercells merged and became one squall line. It developed further and became a bow echo system.

Timeline of the derecho

Minnesota

The most damage in Minnesota occurred at the northern edge in Sibley and McLeod Counties. Winds ranged from 80-100 mph in those two counties.

After the derecho raced through Minnesota, tens of thousands of trees were blown down. There were 500,000 customers without power. Over 100 homes were destroyed or damaged beyond repair. Twenty-two people were injured. The derecho caused $50 million in damage in southern Minnesota and northern Wisconsin.

Wisconsin

The derecho raced across Wisconsin in only three hours killing one person in Washington County when a tree fell through the roof and onto her bed where she was sleeping. It injured 37 people in Wisconsin. Many utility companies and emergency customers said that this was the most damaging straight-line wind thunderstorm event in 100 years. Five thousand homes and businesses were damaged and 24 were destroyed.

An area of south-central, south-east, and east-central Wisconsin reported wind gusts of over 100 mph (160 km/h) from this thunderstorm complex with an all-time official state record gust of 128 mph (206 km/h) 1½ miles (3 km) north-west of Lebanon in Dodge County. As with other derechos like the 4. July 1977 blow-down in northern Wisconsin, there were other unofficial reports of higher winds as well as estimates of such, including winds of 102 mph (165 km/h) sustained for a number of minutes and gusts up to 140 mph (225 km/h) also in Dodge County and/or adjacent sections of Fond du Lac County.

The derecho also caused boating accidents by generating a seiche on Lake Michigan which was reported to be around 10 feet (3 metres) high as it first struck the Michigan coastline of Lake Michigan further north in Muskegon County.

Michigan, Ontario & New York

The storm raced through Michigan in only two hours at an average speed of 70 mph. Four people were killed in Michigan, and 146 were injured. Total damage was estimated at $172 million (1998 dollars). 250 homes and 34 businesses were destroyed. In Grand Haven the Story & Clark smokestack at the Piano Factory Condominiums was destroyed when the force of the high wind caused it to crumble, and trees collapsed all over the city, some falling onto roofs. Damage in Spring Lake was worse, due to a highly localized zone of higher winds. The Mill Pointe Condominiums suffered serious damage, including the collapse of one unit. Others were subsequently removed. A factory lost its roof in the storm, and a number of businesses were damaged severely, one beyond repair. Country Estates Mobile Home park also suffered serious damage. A woman was killed in Pinconning, about 130 miles north of Detroit, when a tree fell on her house. Extensive damage to Grandville (approximately 30 miles inland) led to the city being closed off, with no traffic allowed to enter in the day after the derecho's passage.

This derecho would go on to break the record for biggest power outage ever in the state of Michigan (but later surpassed by the 2003 North America blackout). 860,000 people lost power, slightly more than the amount from the Southern Great Lakes Derecho of 1991. It blew down five 345-kilovolt transmission towers owned by Consumers Energy.

Thirteen counties in Central Lower Michigan were declared federal disaster areas.

One person drowned in Ontario when his boat turned over from the derecho's strong winds. Buildings in Toronto lost numerous windows and significant damage was observed in areas such as Trenton, Napanee, Picton and Kingston. Heavy thunderstorm activity was also reported in Ottawa and Montreal, Quebec but without damage.

It caused $300,000 worth of damage in central New York before dissipating at around 11 A.M. on May 31.

Summary

Overall, the derecho traveled 975 miles from southern Minnesota to central New York in 15 hours at an average speed of 65 mph. It became one of the most damaging derecho events in North America's history, causing $300 million in damage.

See also

• List of notable derecho events
• Spencer, South Dakota tornado

External links and sources

• "Origins And Synoptic Setting For The 30- 31 May 1998 Minnesota To New York Derecho" (NWS Twin Cities, MN)
• "The Southern Great Lakes Derecho of 1998" (Storm Prediction Center)
• "Upper Midwest hit by hurricane-force storm" (CNN)

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