If you live near the river, the gauge to watch is the Missouri River at Boonville. It’s the closest gauge to Rocheport, it’s run by the U.S. Geological Survey, and it updates continuously. You can find current readings on the USGS page for station 06909000, and the National Weather Service tracks the same gauge with forecasts at its Boonville river page. The number they report is stage height in feet above the gauge datum, not depth of the water and not height above sea level. We keep a plain-language version on our own Boonville river gauge page.
The National Weather Service sets the flood categories for Boonville like this: action stage at 18 feet, flood stage at 21 feet, moderate flood at 30 feet, and major flood at 34 feet. In summer the river usually runs well below the action stage; on a normal July day it’s often around 10 or 11 feet. At 21 feet, low-lying rural ground along the river starts to flood. The record crest, about 37 feet, was set during the Great Flood of 1993.
For practical purposes: below 18 feet, things are normal. At 18 feet the Weather Service calls it “near flood” and it’s worth checking daily. At 21 feet the river is out of its banks in the low spots, and that’s when you want to be reading the NWS forecast for the projected crest rather than just the current number. The river can come up several feet in a day after heavy rain upstream, so the forecast matters more than the snapshot. The Weather Service offers free flood watch and warning alerts by email, which is the simplest way to get a heads-up before conditions change.
If Boonville’s reading ever looks odd — a sensor hiccup, or a jump you’re not sure is real — the trick is to check the neighbors. The next gauge upstream is the Missouri River at Glasgow, about 30 river miles up on the Howard County side (USGS station 06906500). Whatever the river is doing at Glasgow is headed our way next, so a rise there is your early look at what Boonville and Rocheport get later. The next one downstream is the Missouri River at Jefferson City, roughly 50 river miles below Boonville at the capital (USGS station 06910450) — handy for confirming a crest has moved past us, or if your plans are downriver.
One thing to keep straight: the numbers don’t carry over from gauge to gauge. Each stage is measured against that gauge’s own datum, so 21 feet at Boonville and 21 feet at Glasgow are two entirely different amounts of water. Glasgow’s categories run higher on the dial — action stage at 22 feet, flood stage at 25 — while Jefferson City’s sit a touch lower than Boonville’s, with action at 21 feet and flood stage at 23. Read each gauge against its own thresholds, not ours.
And those two really are the nearest: there’s no other mainstem Missouri River gauge between Glasgow and Boonville, or between Boonville and Jefferson City. Between the three of them, you can watch a rise work its way down the whole stretch of river that matters to Rocheport.