Extreme drought and a warm autumn have left water levels on the Mississippi exceptionally low for the time of year. This is causing problems for farmers who rely on the river as a travel route for the crops: 60% of US grain exports use the waterway to reach the Gulf coasts.
The total economic loss is estimated to be about $20bn and, despite attempts to dredge the river, it remains worryingly low as the country enters an important month for grain transport.
