The Flood of 1986
September, being somewhat of a transition month between summer and fall, generally brings a taming of the summer heat and thunderstorms. Normal rainfall amounts drop off from the summer maximum and the weather, often, goes into more of a tranquil period before the fall storms begin to rage. But this was not the case on September 10-12th, 1986 in Central Lower Michigan into the “Thumb Region” of Southeast Lower Michigan. The central axis of the flood area extended from north of Muskegon, near Rothbury, east across all of Central Lower Michigan to near Port Sanilac, in Southeast Lower Michigan’s “Thumb Region”. Some major cities in Southeast Lower Michigan affected by the flood included Saginaw, Bay City and Midland. It is interesting to note that the city of Flint actually experienced more severe flooding in September 1985 than it did in September 1986.
Several estimates about the likelihood of such a flood like the one in 1986 were tossed about such as a “100-year flood” or a “500-year flood”. But to the people of the flood stricken area it is known as “The Flood”! Several rain events plagued this area through September but the main one occurred September 10-12th, 1986. The flooding rains were triggered by a nearly stationary front which, like the flood area itself, stretched east-west across Central Lower Michigan. Warm, moisture-laden air from the Gulf of Mexico (enhanced by a moisture plume from remnants of a tropical system over the Eastern Pacific), streamed north and east out of the Midwest, across the stationary front into Central Lower Michigan. To the north, cooler, drier air remained entrenched over Upper Michigan. The upper wind pattern across the Great Lakes was conducive in holding the surface front nearly in place, resulting only in a slow drift to the north through the entire period. This in turn, caused any available moisture pushing north across the front to be wrung out and dumped persistently over the same general area.
An extensive area of heavy rain and severe thunderstorms with torrential rains developed just north of the front and extended west from Michigan into Wisconsin. As the moisture from the south overran the front and fell as heavy rain over Central Lower Michigan, it also traversed the same area from west to east during the two day period. This process of precipitation developing and repeatedly moving over the same area is known all too well by meteorologists and hydrologists as “train-echoing”. This was the primary mechanism for the persistent heavy rainfall during this flood event. Some rain fall totals September 10 to the 12th and for September 1986. At Midland 11.78” (18.35”) MBS 10.09” (16.16”) Saginaw 10.50”(16.06”) Caro 11.57” (18.16”) Bay City 10.67” (15.86”) Here in Grand Rapids 6.43”(11.85”) Muskegon 8.66” (13.55”)
As for the flooding The Cass River at Vassar with a flood stage of 14 feet rose to an unprecedented (and almost unbelievable) 24.82 feet, or better than 10 feet above flood stage! This level of nearly 25 feet is even more astonishing, when you consider the normal height of the river is about 4.5 feet. Likewise, the Cass River at Frankenmuth rose to around 10 feet above its flood stage with 27.52 feet reading (flood stage is 17 feet).
Like many locations in and near rivers and drainage areas, the flooding in the town of Vassar was a nightmare! It was definitely one of the hardest hit areas with all the downtown businesses and about 50 homes being flooded. The flood waters reached to the intersection of Main and Huron St. on the northwest side of the Cass River and extended to the intersection of Huron and East St. on the southeast side. The river rose so quickly and forcefully, that some people barely had enough time to get out. Several people awoke in Vassar to find their streets and cars covered in rushing water as the raging river surrounded their homes and businesses. But further downriver on the Cass, at Frankenmuth, vigorous sand bagging on top of permanent levees protected the downtown area from any serious flooding.
Across Central Lower Michigan, 22 counties were declared disaster areas. This encompassed nearly 14,000 square miles and where 1.8 million people lived. Even though damage was estimated between $400 to $500 million (1986 dollars), it hard to put a dollar figure on the huge amount of personal items these people lost and also, the emotional scars some still carry with them. To give an idea the volume of water that fell over Saginaw River basin, it was estimated by the state hydrologist (at that time) that if that water could be drained into Lake St. Clair, it would raise its level 10 feet! The Bay City Times, in retrospect, summed up “The Flood” well by telling their readers to just scan the “D” listings in the dictionary, “It’s all there, Downpours, Drenching, Devastation and Disaster”!
This information is from a write up from the NWS Detroit.
Slim
Barely hit 80 degrees yesterday and only 82 today! So much for the mid 80’s that some were predicting! Incredible!
86 here – which is 10 degrees above average.
Yes GR is the place to be!
Another warm day. A bit more humidity today. At least there’s a breeze. 85 here currently.
Go Green!
Go White!
Sorry, Go BLUE!! 🙂 honestly I really don’t care in the end but we have always been a UofM household.
Thanks Slim! I don’t recall that flood, but I would have been in early high school and probably not paying much attention to the weather. Back then I was more focused on other “important” things like racing my car at the Martin drag strip
It was more to the north of Grand Rapids, Holland but there was a lot of street flooding here in Grand Rapids.
Slim
This has been quite a nice end to summer. The first day of fall is only 12 days away which is hard to believe. It’s strange to think that Christmas season is only a couple months away
The official H/L at Grand Rapids yesterday was 81/56 there was no rain fall and the sun was out 98% of the time. The overnight low here both in MBY and at GRR has been 62 and that is the current temperature with some clouds. For today the average H/L is now down to 76/55. The record high of 94 was set in 1931 and 2013 and the record low of 36 was set in 1917 and 1969. The sun rises today at 7:16AM and set at 8:01 PM. It looks to become rather wet for Sunday and Sunday night.… Read more »
Thank you GR National Weather Service! Your state of the art equipment yields 100% accurate temp readings! Keep up the good work!
I am not sure about being 100% accurate but in looking at the mean temperatures for the month of September so far, the mean temperature at Grand Rapids and Lansing are both 69.1. At Holland the mean in 69.3. So, the overall temperature profile has been rather stable in the area. But that said the departures from average so far are +1.8 at Grand Rapids. +2.8 at Lansing and +2.9 at Holland. That would indicate that Lansing and Holland were colder than Grand Rapids in years 1991 to 2020. And that seems to carry over into other months as well.
Slim