The near-record cold of between -20°C to -31°C followed a winter storm that dumped more than 30cm snow in some areas, closing roads in northwest Indiana and preventing workers from reaching pork plants, grain elevators and processing plants in the northern half of the state, industry sources said.
Ice build-up in the Illinois River slowed the flow of grain to export terminals at the Gulf of Mexico, where some 60% of US maize, soya beans and wheat exit the country.
Snow cover protects dormant wheat when temperatures dip below zero. Without sufficient cover, damage to exposed wheat can prevent the crop from reaching its full potential the following summer.
