Wyatt, Mo. ? The dramatic, late-night demolition of a huge earthen levee sent chocolate-colored floodwaters pouring onto thousands of acres of Missouri farmland Tuesday, easing the threat to a tiny Illinois town being menaced by the Mississippi River.

But the blast near Cairo, Ill., did nothing to ease the risk of more trouble downstream, where the mighty river is expected to rise to its highest levels since the 1920s in some parts of Tennessee, Mississippi and Louisiana.

The Army Corps of Engineers was considering making similar use of other “floodways” — enormous basins surrounded by giant levees that can be opened to divert floodwaters.

A staccato series of explosions lit up the night sky Monday over the Mississippi with orange flashes and opened a massive hole in the Birds Point levee. A wall of water up to 15 feet high swiftly filled corn, soybean and wheat fields in southeast Missouri.

Upstream at Cairo, which sits precariously at the confluence of the swollen Mississippi and Ohio rivers, preliminary readings suggested the explosion worked.

But across the river, clearing skies gave a heartbreaking view of the inundation triggered by the demolition. The torrent swamped an estimated 200 square miles, washing away crop prospects for this year and damaging or destroying as many as 100 homes.

A group of 25 farmers sued the federal government Tuesday, arguing that their land had been taken without adequate compensation.