A warm and muggy airmass persisted over southeast Michigan.  A complex of thunderstorms moved east across northern Michigan in the early morning hours.  Outflow from this thunderstorm complex moved south into southeast Michigan as a miniature cold front, and thunderstorms redeveloped along the leading edge of this outflow in the afternoon.  Meanwhile, thunderstorms also developed in northeast Indiana, along the edge of a deck of low clouds.  These separate areas of thunderstorms would merge over Metro Detroit in the late afternoon and early evening, producing tremendous amounts of rain.  Many places had seen heavy rain the day before, and thus the area was quite vulnerable to flooding.At Detroit Metro Airport, 3.71 inches of rain fell on the 11th.  This was the wettest September day ever in Detroit, and the 5th wettest day of all time.  This was on top of the 1.65 inches that fell the day before.  National Weather Service radar estimated around 5 inches of rain fell on the 11th in a swath from Brownstown Township to Allen Park in Wayne County.  In Washtenaw County, 2.26 inches of rain fell in Ann Arbor, after 1.32 inches the previous day.The storms had a broad impact.  Over 30,000 households were affected by power outages.  About one hundred flights out of Detroit Metro Airport were cancelled, and numerous people were stranded at the airport overnight due to the multitude of flooded roads in the area.  A collision on Interstate 94 in Harrison Township (Macomb County) during a downpour closed the highway for two hours.  Sewage overflows were common in Wayne County, as the water treatment system was quickly overwhelmed; the failure of some pumping operations due to power outages contributed to the sewer backup.  Several lawsuits were filed in connection with damage caused by raw sewage.

Lightning in MACOMB, MICHIGAN
From 11-SEP-00 18:00:00 to 11-SEP-00 18:00:00 (EST)
Location: WARREN
Reported by: NEWSPAPER

Lightning struck the ground at an athletic field as kids were rushing to leave soccer practice.  One boy close to the strike was thrown to the ground.  He was not seriously hurt, though he stayed overnight at a local hospital for precautionary reasons.

Flash Flood in OAKLAND, MICHIGAN
From 11-SEP-00 17:40:00 to 11-SEP-00 22:45:00 (EST)
Location: WATERFORD
Property damage: 10K
Reported by: TRAINED SPOTTER

Central and eastern Oakland County received an inch or so of rain on the 11th.  With soils in the area soaked through from very heavy rain the day before, flooding developed quickly.  The upper reaches of the Clinton River exceeded its banks in Waterford and Rochester.  Street flooding worsened to the point where flood waters entered a business in Walled Lake.

Lightning in OAKLAND, MICHIGAN
From 11-SEP-00 16:30:00 to 11-SEP-00 16:30:00 (EST)
Location: MILFORD
Property damage: 10K
Reported by: NEWSPAPER

The 911 phone system at the Milford Police Department was zapped by lightning, causing substantial damage to electronic equipment.

Flash Flood in LENAWEE, MICHIGAN
From 11-SEP-00 17:10:00 to 11-SEP-00 22:45:00 (EST)
Location: ADRIAN
Property damage: 15K
Reported by: LAW ENFORCEMENT

Low lying intersections in Adrian flooded rapidly.  Water was high on many streets in the city, flooding and damaging several vehicles.

Flash Flood in WASHTENAW, MICHIGAN
From 11-SEP-00 18:10:00 to 11-SEP-00 22:45:00 (EST)
Location: ANN ARBOR
Property damage: 40K
Reported by: LAW ENFORCEMENT

Water levels in Ford Lake, and its inflowing streams, resulted in erosion of the roadway along Ford Lake Dam.  In addition, street flooding in the city of Ypsilanti was widespread.  Ann Arbor had numerous stalled cars and flooded intersections, including a foot of water over Huron Street and Washtenaw Avenue.  The heavy rain indirectly contributed to a fatality, when a female pedestrian was struck and killed by a University of Michigan bus during a blinding downpour.

Thunderstorm Wind in GENESEE, MICHIGAN
From 11-SEP-00 15:25:00 to 11-SEP-00 15:25:00 (EST)
Location: FLINT
Magnitude: 50 E
Property damage: 12K
Reported by: BROADCAST MEDIA

A tree was downed onto a car on Russell Avenue near Summit Street.  A woman at scene suffered a cut to her arm, necessitating a trip to the hospital.

Flash Flood in WAYNE, MICHIGAN
From 11-SEP-00 17:18:00 to 12-SEP-00 04:20:00 (EST)
Location: BELLEVILLE
Property damage: 20M
Reported by: LAW ENFORCEMENT

Widespread, severe urban flooding resulted in a Presidential Disaster Declaration for Wayne County.  The communities most severely affected included Allen Park, Dearborn, Dearborn Heights, Ecorse, Lincoln Park, Melvindale, Riverview, Southgate, Taylor, Van Buren Township, Wyandotte, and Wayne.  Over 15,000 residences and other structures in Wayne County suffered at least some flood damage.  Individual communities tallies included: 2700 homes in Allen Park, at least 500 in Lincoln Park, 2200 in Southgate,  and 8000 in Wyandotte.  In Allen Park, an estimated 40% of all streets flooded at some point during the event.  Underpasses flooded in Dearborn and Dearborn, and street flooding was widespread, especially near Ecorse Creek.  The Southfield Freeway were covered with two to three feet of water.  In Detroit, the failure of a pumping system caused the Lodge Freeway to flood with two to three feet of water.  The basement of city hall was damaged by flood waters in Lincoln Park, and street flooding was also widespread.  In Riverview, street flooding was again widespread, with water approaching the doorsteps of some homes.  A home in Riverview had its basement collapse.  The Romulus area saws numerous roads flood, especially around Detroit Metropolitan Airport; numerous motorists had to be rescued from their stalled and stranded vehicles between 6 and 8 pm.  Three feet of water covered Fort Street in Wyandotte.  The Governor of Michigan estimated $19 million in personal property damage in Wayne County, but said that estimate was "conservative".