Low flood potential seen in area tributaries

A shortage of precipitation this winter across Northeast Missouri doesn't necessarily mean the Mississippi River will be on its best behavior this spring. According to the National Weather Service's (NWS) spring flood outlook there will be near normal flood chances along the Mighty Mississippi.

According to the report issued last week the outlook is based on current streamflows and soil moisture over the area, upstream snowpack in the Mississippi basin and forecast rainfall through the next three months.

Based on current conditions there is a 68 percent chance of minor flooding in Hannibal. Minor flooding in America's Hometown occurs when the river rises to between 16 and 22 feet. The possibility of moderate flooding (between 22 and 24 feet) is pegged at 16 percent. The likelihood of a major flood (over 24 feet) stands at 9 percent.

The high-water mark of 2017 in Hannibal was seen on May 3 when the river reached 20.34 feet.

According to NWS records, the last moderate flood in Hannibal occurred on Dec. 29, 2015, when a crest of 22.16 feet was seen. The most recent major flood crest in Hannibal happened on July 8, 2014, when the river topped out at 26.68 feet, which ranks No. 6 in recorded history.

Hannibal's all-time record crest was 31.80 feet on July 15, 1993.

In Saverton, at Lock and Dam 22, the possibility of minor flooding (between 16 and 20 feet) is 56 percent, based on current conditions. Regarding moderate flooding (between 20 and 22 feet) the outlook is 28 percent. As for major flooding (over 22 feet) the probability is 18 percent, which represents the highest percentage of any area location along the Mississippi River between Lock and Dam 20 at Canton and Lock and Dam 25 in Winfield.

In Pike County, Mo., the minor flood outlook (between 15 and 20 feet) is 70 percent, based on current conditions. The likelihood of a moderate flood (between 20 and 25 feet) is gauged at 26 percent. As for major flooding (over 25 feet) the probability is less than 5 percent.

According to the NWS, while there has been a “pronounced precipitation deficit” in the area, the possibility of flooding this spring along the Mississippi River is due to near normal snowfall, on average, this winter in the upper Mississippi River basin - Iowa, southern

Wisconsin, and northern Illinois. And while snow totals are low across the upper Midwest - Minnesota and northern Wisconsin - soil moisture across the upper Mississippi

watershed is mostly near to above seasonal norms.

In contrast to the Mississippi River, the flood potential on local tributaries, such as the Salt River, North River and South Fabius River, is considered low after more than four months of below average precipitation across Missouri and Illinois.

On the North River in Palmyra, there is a 37 percent chance of minor flooding, a 25 percent chance of moderate flooding and a less than 5 percent chance of major flooding. On the South Fabius River at Taylor, there is a 27 percent chance of minor flooding, a 8 percent chance of moderate flooding and a less than 5 percent chance of major flooding. On the Salt River at New London, the odds of any kind of flooding are gauged at less than 5 percent.

Reach reporter Danny Henley at danny.henley@courierpost.com