Thousands of festivalgoers are settling into campgrounds along the Niangua River this week for the 26th annual Gathering of the Juggalos, running August 19-22 in Macks Creek. But heavy rain in tonight's forecast could put a damper on the festivities.

Camden County is under a Level 2 of 4 risk for flash flooding Tuesday night into Wednesday morning as widespread rain moves through the region.

That risk is worth a closer look, because the festival grounds sit right up against the river on both ends. The organization's event map shows campgrounds on the eastern side of the property, along with several stages, pavilions and gathering spaces to the northwest, all sitting close to the Niangua's banks.

FEMA's National Flood Hazard Layer for the site shows just how exposed these areas are. The map shows two flood zones cutting through parts of the campgrounds and event spaces on both the east and northwest sides of the property.

The easier one to spot is the blue-shaded Zone AE; that's FEMA's 1-in-100-year floodplain. That designation means any given year carries about a 1% chance of flooding that severe, which works out to roughly a 26% chance over the life of a 30-year mortgage. It's a meaningful risk for anyone camping or set up in that zone.

There's also a much thinner, harder-to-spot band of orange bordering the blue: that's the 0.2% annual chance flood hazard, or the 1-in-500-year floodplain. It's a lower-probability event, but it still marks ground the river has reached before and could reach again.

Luckily, nothing in the current forecast points to the kind of extreme rainfall that would test those flood zones this week. Parts of northern Missouri could see 1 to 2 inches of rain Tuesday into Wednesday, but totals over Macks Creek itself are expected to stay under a quarter inch.

In fact, Camden County has been running a rainfall deficit of more than an inch and sits in a light drought right now, so the ground has room to soak up what does fall.

Still, flash flood risk can change quickly with slow-moving storms, and campers in low-lying spots near the river should keep an eye on updates through the week.