Grain growers in the US are nervously waiting for the country's cold snap to clear so they can inspect their crops.
Snow and temperatures below minus 30 degrees Celsius have created transport nightmares for farmers across the country.
Chicago futures trader Jack Scoville says the US's main wheat crop, the hard red winter wheat, appears to have escaped damage.
But he says the soft red winter wheat and oranges will be the hardest hit crops.
"With the type of extreme temperatures that we've seen, there is the potential for some loss," Mr Scoville said.
"Exactly how much the loss is nobody really can put a handle on just for right now.
"But it looks like maybe 15 per cent or so of the soft red winter area could be affected by some type of loss and that translates in to five per cent of the total wheat crop here."
© ABC 2014
08:19 EST Winds described as "tornado-like" by emergency workers have left a trail of damage in Tasmania's north-west overnight, injuring one man and causing widespread power cuts.