When the dew on Adam Thomas’s Illinois farm evaporates in the morning, he begins harvesting soybeans. Dry weather accelerated the work this year, allowing him to begin earlier. His issue was bringing the soybeans to market.

Drought affects approximately 60% of the Midwest and northern Great Plains states. Over the last two months, nearly the entire length of the Mississippi River — from Minnesota to the river’s mouth in Louisiana — has received less rain than usual. As a result, river water levels have dropped to near-record lows, causing a disruption in ship and barge traffic that is critical for transporting recently harvested agricultural goods such as soybeans and corn downriver for export.

Although scientists believe that climate change is increasing temperatures and making droughts more common and severe, a weather expert believes that the current drought affecting the central United States is more likely a short-term weather phenomenon.

The lack of rain has had a significant impact on commerce. According to industry estimates cited by the federal government, the river transports more than half of all U.S. grain export, but the drought has reduced the flow of goods by about 45%. Rail shipments, an alternative to shipping goods by barge, are also becoming more expensive.

Thomas farms near the confluence of the Ohio and Mississippi rivers and does not have enough grain storage to cover the high shipping costs.

Climate change is generally causing wetter conditions in the Upper Mississippi River region, but lower water levels have revealed previously inaccessible areas in recent months. Thousands of people walked across a typically submerged riverbed last weekend to reach Tower Rock, a protruding formation about 100 miles (161 kilometers) southeast of St. Louis. It’s the first time since 2012 that tourists have been able to make the journey while remaining dry. Four-wheeler tracks snake across vast stretches of exposed riverbed on the Tennessee-Missouri border, where the river is a half-mile wide.

Barges are at risk of collapsing and becoming stuck in the mud. The US Coast Guard reported at least eight such “groundings” earlier this month. Some barges make contact with the bottom but do not become stuck. Others require the assistance of salvage companies. Barges are advised to lighten their loads to avoid sinking too far into the water, but this means they can carry fewer goods.

To ensure that vessels travel safely, federal officials meet on a regular basis, take into account the depth of the river, and consult with the shipping industry to determine local closures and traffic restrictions. Hundreds of barges may queue to wait when a stretch is temporarily closed.

According to Mike Steenhoek, executive director of the Soy Transportation Coalition, storage at barge terminals is filling up in some places, preventing more goods from arriving. He compared the influx of grain into a weakened river transportation system to “connecting a garden hose to a fire hydrant.” Farmers’ high costs have caused some to delay shipping their goods, he added.

Much of the river is still accessible to tourists. Cruise ships are designed to withstand the extremes of the river: According to Charles Robertson, president and CEO of American Cruise Lines, which operates five cruise ships that can carry 150 to 190 passengers each, big engines fight fast currents in the spring and shallow drafts keep the boats moving in a drought.

However, nighttime operations are restricted to assist ships in avoiding new hazards exposed by the drought. Furthermore, some landing areas are inaccessible due to low water — the river has dried out along the edges. When a cruise ship couldn’t get to a ramp that normally loads passengers in Vicksburg, Mississippi, the city laid gravel and plywood to create a makeshift walkway with the help of locals. It adds to the adventure for some.

Drought has been a persistent issue in California, which recently experienced its driest three-year stretch on record, straining water supplies and increasing wildfire risk. Droughts are becoming more common and severe as a result of climate change.

It is unknown how long the drought will last.  In the near term, there is a chance for rain, but NOAA notes that in November, below average rainfall is more likely in central states such as Missouri, which would extend shipping problems on the river. In some northern states including Michigan, the winter may bring more moisture, but less rain is expected in southern states.