Awakened by a loud roar around midnight, residents of a Wheeling apartment complex watched in awe as winds gusting up to 80 m.p.h. peeled away part of their roof during a tempest that uprooted trees and disrupted electrical service throughout northeastern Illinois.
“It felt like we were in a movie, except that it looked too fake,” said Bob Olson, a resident of the Pine Hill Apartments, 500 Manda Lane, where Friday’s daybreak revealed that about one-quarter of the roof was missing.
National Weather Service meteorologists described the wind as a microburst–a dangerous downdraft that can pack the punch of a tornado.
Elsewhere, the storm shook houses and buildings as it raced toward Chicago from Rockford. Gusts of 60 to 80 m.p.h. ripped large tree limbs from their trunks, tossing them against power lines, houses and cars.
The worst damage occurred in the north and northwest suburbs, but homes and business throughout the metropolitan area lost power. By 2 a.m. Friday, the high winds had cut electricity to about 155,000 Commonwealth Edison Co. customers. Utility crews worked throughout the day to restore service and expected to complete the job Friday night.
Many north and northwest suburban schools were closed for the day because of power outages, and traffic crawled along major thoroughfares because of darkened traffic lights. Municipal public works employees closed streets as they tended to downed tree limbs.
At the DuPage County Airport, winds gusting to 60 m.p.h. flipped a small plane onto another plane.
The high winds were a product of a dying thunderstorm, said Richard Brumer, a National Weather Service meteorologist.
“What happens is that the air gets cold in the storm, and the storm starts to die,” he said.
All storms are developed around rising warm air called an updraft. But if that updraft cools, “it can’t hold the storm together anymore,” Brumer said. The high winds that usually travel thousands of feet above the storm start dropping, and they accelerate as they plummet to earth.
Those downdrafts hit the ground in towns such as Carpentersville, which clocked 75 m.p.h. winds, and Arlington Heights, West Chicago and Lake Villa, which all recorded gusts around 60 m.p.h., Brumer said.
Wheeling was a special case–a microburst, Brumer said. There, a second front of winds formed behind the storm. When those winds caught up with the first set of winds, they created the 80 m.p.h. gusts that forced apartment residents into the basement for shelter as the roof opened up to the sky.
A similar phenomenon occurred in 1990 in Streamwood, Brumer said, when a 30-second microburst clocked at 120 m.p.h. caused about $10 million in damage.
Residents of the Pine Hill apartments appeared dazed Friday as they walked through the parking lot strewn with chunks of the tar roof and tree branches. Olson’s car was one of several that witnesses said were lifted by the wind, which then dropped a large section of the roof under the vehicles.
Uprooted trees smashed through other cars in the parking lot, while nearby a motorcycle stood unscathed.
In Lake Zurich, an early morning collision between a semi-tanker carrying hot asphalt and a pickup truck at U.S. Highway 12 and South Old Rand Road may have been caused by an outage at the traffic signals there, police said. No one was seriously injured, they said.
