CHICAGO — The Windy City on Monday marked the end of the wettest month in Chicago weather history--almost a foot and a half of rain that washed out a barrel of records kept by the National Weather Service here.
The rains of August, which caused an estimated $100 million in damage, fell on 16 of the month's 31 days. In an average year, six days of rain is considered normal for the usually hot and sunny month.
The total deluge, 17.1 inches, was almost five times the average for August and more than has ever fallen in any month in more than a century of record keeping.
And the 9.35 inches of rain dumped during a stormy 12 hours on Aug. 14 was the most ever to fall on the city in any 24-hour period. That storm had the impact of a midwinter blizzard, disrupting air travel nationwide, flooding streets and expressways and forcing cancellation of scores of public events. Even the Weather Bureau was forced by floodwaters to close for several hours.
The storms flooded more than 16,000 homes and businesses in Cook and Du Page counties.
Chicago's beaches were closed for several days after millions of gallons of raw sewage were released into Lake Michigan as part of an emergency flood control plan.
Service at O'Hare International Airport, one of the busiest in the world, was disrupted for three days. The airport, a massive complex on the northwest side of the city, was surrounded by water for 18 hours, making it impossible for arriving passengers to leave the terminal and for departing passengers to reach their planes.
In fact, the only way to reach the airport was by plane, and news agencies chartered aircraft from Midway Airport on the city's southwest side to fly to O'Hare to cover the story.
"Never have we had anything quite like that in the middle of August in Chicago," said Joe Hopkins, spokesman for United Airlines, the city's largest air carrier. "Our on-time performance systemwide for August is going to go down a few percentage points below July and June because of all that heavy rain."
Powerful thunderstorms hit the city four different days during the month, three times the average for August.
"It was very unusual in terms of precipitation," said National Weather Service forecaster Paul Merzlock. "We were in a very tropical-type atmosphere, something we'd expect to find in the Gulf Coast region."
"We had flash flooding, and that is tougher than traditional river flooding to fight because they are not predictable," said Gregg Durham, assistant director of the Illinois Office of Emergency Services. "Sandbags don't do any good in a flash flood. . . . It was a real mess for a while.
"A lot of people realized that no one can harness the forces of nature," Durham added, "and they learned that concrete and asphalt make a lousy sponge."