From the worst floods in the Midwest grain belt in 15 years to drought in California, damage to crops from inclement weather has topped $8 billion so far this year, the largest U.S. farm group said Wednesday.

Water pours out of the Coralville Reservoir emergency spillway onto road, Johnson county, Iowa City, Iowa.

The damage could rise or contract, depending on weather conditions for the rest of the growing season in the United States, the world's top exporter of corn, soybeans and wheat, the American Farm Bureau Federation said.