Forecasts of Flood Crests Raised by National Weather Service

Is downtown St Louis safe to stay during the flood season? Or should we move somewhere to escape the flood? So scary…

At least 24,000 people have been forced to leave their homes in Iowa because of floods, and nearly 4,000 homes have been evacuated in one of the worst affected area - Cedar Rapids city. It is really scary!

Downtown St. Louis should be safe, the flood will be below the major flooding stage here, since the major flood on the Mississippi is joined by the lower Missouri and Illinois Rivers here. However, the Army Corps of Engineers has determined that parts of the levees protecting the Metro East area (in Illinois) are structurally deficient, and have a higher potential of failure by underseepage. Therefore, if you are on the east side of the river it is wise to keep an eye on the levee situation.

That is scary. I remember the sand boils over in IL in 1993. It got closer to the tops of the levees then than I ever remembered in the decades I’ve lived in this area. I noticed many areas have installed additional swale areas for the waters to go since 1993. That should have taken stress off many of the smaller levees. Hopefully, the selfish ones won’t be tempted to destroy good levees to save their own land like they did in 1993. Start the levee patrol guys to catch the good old boyz before they bust another one open! My vote is to spend on our levees and quit playing god in the sands! Hear me GB????

Tim,

I stumbled upon this blog by total accident. Can you please explain what has caused the record flooding this spring in the Midwest? I have yet to hear an explanation that makes perfect sense. Dave Price, the weather correspondent on the CBS Early Show, mentioned that the flooding was caused by a large High in the mid-Atlantic blocking other weather systems from making their usual trek across the country. It was this High, he said, that caused much of our record heat last week along the East Coast.

Jeff Masters, one of the founders of the Weather Underground site, said the flooding was cuased by the reminants of Tropical Storms Alma/Arthur. However, I believe these systems clung to and decayed over Central America/extreme southern Mexico.

Various other sources, mainly newspapers and the Associated Press, have posited the belief that this flooding was caused by an excess dip in the Jet Stream bringing warm moist air from the Gulf of Mexico and cold air from Canada. Where the air masses collided — the Midwest — heavy thunderstorms and tornadoes repeatedly formed.

Are any of these theories correct? Your informed opinion would be much appreciated. And, for the record, I live in North Carolina. I find the weather very interesting to follow, though, so keep up the great job. And best wishes to you all in this flooding.

- Brian

Hi Brian,

Thanks for your thoughts, the floods are affecting a lot of people in this region. The flood crest is now predicted to reach 39.8 feet, up almost 4 feet from earlier forcasts and just inches below the top of the major flood level where the Choteau Island levee, protecting 2400 acres, is overtopped.

The floods have been caused by a combination of factors- heavy snow melt in the upper mid west, heavy rain falls this spring, saturated soils. That brings a lot of water into the river systems. The flood heights have been raised considerably (maybe as much as 10 feet) by the different navigational and “flood control” structures that have been built in the river, including the levees themselves, wing dikes, and other piles of rock (like chevrons) that reduce the width and cross sectional area of the river channels, causing the water to rise faster, and higher. Some of this is explanined in the links in the main story above, and in the blog below “Mississippi Floods Could be the Worst Since 1993″

There is a long story that aired on Public Radio today about these floods, and what caused them, and you can listen or download the MP3 at this site:

http://www.kcrw.com/news/programs/tp/tp080616is_midwestern_flood_

Tim,

Thanks for the explanation and the link to the radio program. Now it makes sense. The flood has been caused by several factors: too much snow, followed by too much rain; too much development along flood plains; and too much involvement in placing structures into the river to aid in navigation/water flow control.

Although it’s truly a very sad situation for all who currently are and those who will be affected by the flood waters, it’s so nice to see Midwesterners have a much better attitude when being confronted by this disaster. This is far different, and much more refreshing, than the way some folks who live along the Gulf Coast responded to Hurricane Katrina three years ago. If this were the only reason (it’s not), you all should be commended for the can-do response and chipper attitude in the face of adversity. Hang in there. You all are definitely in our thoughts and prayers in this and other parts of the country.

- Brian