Rain upstream could push the Mississippi River to flood stage in the St. Louis area by next week according to National Weather Service projections.
Some metro-east communities including Alton and Grafton are already seeing minor flooding, and conditions could rapidly worsen with water heading downstream.
U.S. Army Corps of engineers spokesman Mike Petersen said flooding forced the closing of Lock and Dam 24 about 90 miles north of St. Louis at Clarksville, Mo.
Right now thats the only lock and dam we anticipate having to close, Petersen said.
But that depends on what the weather is going to do.
While residents saw mostly dry and mild temperatures for July 4 festivities, the forecast calls for a chance of thunderstorms to creep back into the picture Saturday night and could be a factor in the early part of next week.
The most important thing isnt rainfall, its where it falls, Petersen said. If it falls here, thats not going to affect us as much as it will if it rains up north where the flooding problems have been much worse. Illinois state climatologist Jim Angel said the recently completed month was the eighth-wettest June on record for Illinois with about 25 percent more precipitation falling than in an average year leaving the ground saturated.
The statewide average precipitation for June 2014 in Illinois was 6.78 inches 2.58 inches above the average, Angel said. The rainfall was widespread across the state."
Much of the corn belt was wetter than average for June with precipitation departures from average in the range of 6-10 inches. Thats more than double the average in many locations.
The results are high flows on many rivers and streams and flooding along the main stem of the Mississippi River south of Dubuque, Iowa.
The Mississippi was at 25.17 feet at the St. Louis riverfront earlier this week, but, if current conditions remain, it is expected to reach action stage of 28 feet by Monday morning. By Wednesday it is predicted to reach 29.1 feet, which is minor flood stage.
At the Mel Price Lock and Dam in Alton, the river was already into the action stage at 19.91 feet. It is expected to reach minor flood stage by Saturday when it will pass 21 feet on its way of a predicted crest of 24.9 feet by Wednesday.
Further north in Grafton, the Mississippi is into minor flood stage at 20.64 feet. It is expected to reach moderate flood stage of 25.5 feet on Thursday.
In addition to closing Lock and Dam 24, the Corps of Engineers opened its emergency operations center due to the potential of flooding, Petersen said.
That gives us the capability to provide people and supplies rapidly if things should get worse, Petersen said. We want to make sure we have folks available to help over the holiday weekend if the need should arise.
Petersen said the flooding upstream wont necessarily translate into problems in the heart of the metro area. He said the wider river near the St. Louis riverfront can handle a lot more water than places upstream, which flood more easily.
In addition to being wetter than usual in June, Angel said it also was hotter. The month was 1.1 degrees warmer than average with a statewide average temperature of 72.9 degrees.
Contact reporter Scott Wuerz at email@example.com or call 239-2626.