About 31 cars derailed after the tracks reportedly collapsed due to saturation from flood waters from adjacent Little Rock River. The cause has not been confirmed, although Iowa Governor Kim Reynolds attributed it to an intense storm and flash flooding in an emergency proclamation issued by her office on Saturday.
Cleanup of an oil spill caused by the derailment of almost three dozen oil tankers in northwestern Iowa has begun.
Crews are trying to determine how quickly crude oil leaking from derailed railroad tanker cars in northwest Iowa will reach cities downstream.
BNSF had hazardous materials and environmental experts on the scene and had begun cleanup within hours of the derailment, Williams said.
Crews are working to clean up a BNSF oil train derailment in Iowa that dumped crude into floodwaters, while officials seek to get a handle on the extent of the spill and its cause.
Olson says the city, with a population of almost 3,400, will use the rural water supply until testing by the Iowa Department of Natural Resources confirms the safety of the city's drinking water.
City spokesman Travis Olson says 12 blocks of the city with between 50 and 70 homes - were evacuated Thursday when the Rock River came out of its banks.
"We've had skimmers working since yesterday on the floodwater south of the site".
Despite the rising water outside, the oil spill turned Rock Valley's focus to the safety of the water inside, ultimately deciding to turn off all locally sourced water.
The National Weather Service says the Rock River is expected to crest later Friday about a foot below the 2014 record of almost 23 feet (7 meters), when several Rock Valley homes were damaged by the floodwater. The train was carrying oilsands from Alberta, Canada, to Stroud, Oklahoma, for ConocoPhillips.
Rock Valley, a small city just to the southwest of Doon where more than 30 oil tanker cars derailed into floodwaters, has shut off all its drinking water wells.
About 100,000 gallons had been hemmed off using booms out of the estimated 230,000 gallons spilled, BNSF said in a statement on Saturday.
It's also unclear how many cars derailed and what caused the derailment.
Metropolitan Utilities District said it was monitoring pumps it uses to pull drinking water from the Missouri.