The Rhine River is set to become virtually impassable at a key way point in Germany, with shallow water choking off shipments of energy products and other industrial commodities along one of Europe’s most important waterways.

The marker at Kaub, west of Frankfurt, is forecast to drop to the critical depth of 40 centimeters (just under 16 inches) early on Aug. 12, according to the German Federal Waterways and Shipping Administration. At that level, most barges that haul goods from diesel to coal are effectively unable to transit the river. It’s set to continue dropping, to 37 centimeters the following day.

Europe is facing its worst energy crisis in decades as Russia curbs natural gas flows, with regional tensions high over its invasion of Ukraine. That’s sent prices soaring and pushed companies to use more oil and coal instead. The energy crunch has spilled over into the broader economy, sending factory costs surging and threatening to push some of the continent’s largest economies into recession.