Searing heat has devastated wheat fields across northern Europe and a combination of dry conditions and extreme rain in the Black Sea have hit output estimates, with prices soaring on fears of further crop damage.

Evidence of serious harm to crops is growing as harvesting heads north in Germany, the European Union's second-largest wheat producer, and in Scandinavia, prompting further cuts to estimates for the 28-member bloc.

"The situation is catastrophic in northern Europe," Strategie Grains head analyst Andree Defois said on Thursday.