Residents of Iowa County were forced to evacuate as the swollen Missouri River caused a breach in one of its levees. What I found interesting was a description of a sand boil geyser:
A Black Hawk helicopter was dispatched to dump 1,000-pound sandbags on the failing earthen berm near Hamburg in hopes of closing a “boil” in it. The one- to one-and-a-half inch (2.5-3.8 cm) hole is creating a small geyser of water to shoot onto the dry side of the levee because of the water pressure, said Derek Hill, head of Iowa Homeland Security and Emergency Management.
[Source: Reuters via ASCE SmartBrief]