The trade war hit. These U.S. ports felt the crush of Trump’s tariffs.

President Donald Trump made his mark on the economy during the first months of his second term by imposing historically high tariff rates – throwing the supply chain into a state of unpredictability.

In early April, ships floated into West Coast ports stacked with goods from China. By May, the number of ships had significantly dipped, and they arrived with far fewer containers.

Fluctuating trade policies are causing disruptions and uncertainty for ports and businesses. The number of container ships, which carry everything from Christmas trees to T-shirts across the ocean, climbed during many weeks early this year as retailers stockpiled goods before expected tariffs. But Trump imposed 145% tariffs on Chinese goods in early April, leading to a 25% slowdown of container ships from China arriving at major West Coast ports in the weeks following compared with the a year before, according to a Washington Post analysis of data from the Marine Exchange of Alaska and Maritime Information Services of North America. (U.S. officials have since lowered those rates, at least temporarily, after talks with Chinese counterparts.)

Shifting tariff policies have challenged importers and retailers, while straining the global supply chain.

“What you’re looking for is predictability and stability and reliability,” said Judah Levine, head of research at freight-booking platform Freightos. “And every time there’s a start and stop, there’s a cost.”

Twenty-five fewer container vessels reached the West Coast ports in the five weeks between late April and late May, meaning roughly 325,000 fewer containers on average reached U.S. shores.

When a drop like this happens, it ripples across the supply chain. Longshoremen don’t have as many containers to unload, truck drivers don’t have as much cargo to carry, importers have to reach into their storage for goods – and ultimately, shoppers might see shortages of some products.

“The whole system has less things to move, so there’s less work to go around,” said Capt. Kip Louttit, executive director of the Marine Exchange of Southern California.

At the Port of Los Angeles, which calls itself the busiest container port in the western hemisphere, 17 vessels canceled their arrival in May. That would have accounted for about 225,000 container units that the port was expecting and never received, said the port’s executive director, Gene Seroka. At the ports of Seattle and Tacoma, international imports in the last week of May dropped more than 40% compared with the weekly average last year.

The May slowdown of container ships into U.S. ports was a stark drop.

Now, there are many signs that shipments are picking up again, after Trump paused the highest tariffs on Chinese goods last month.

“It’s like being yanked around by a chain,” Toshiko Grace Hasegawa, Northwest Seaport Alliance co-chair and Port of Seattle commissioner, said of the effects of the constant policy changes.

Early in the year, under the threat of upcoming tariffs, importers hurried to beat the clock, rushing shipments through customs. That flurry of activity temporarily buoyed trade flows and helped retailers ward off shortages and higher prices.

Still, nationwide, Census Bureau data shows a 20% year-over-year drop in Chinese imports in April. The United States relies heavily on trade with China; its second largest trading partner. The impacts of the trade war have been swift: Imports from China fell to $25.4 billion in April, the lowest level since March 2020, when the pandemic took hold of the U.S. economy.

That data, which tracks the value and volume of imports by type of good, shows shipments to five major West Coast ports fell a more modest 14%, cushioned by a surge in early April.

When Trump announced a 145% levy on Chinese goods, it effectively ground trade to a halt because importers couldn’t afford to bring goods in at such a high markup. Many companies didn’t think consumers would be willing to pay enough to make up the extra cost of goods, and some smaller firms couldn’t secure the financing to buy their usual wares anyway. Then last month, U.S. and Chinese officials held talks and announced tariffs would temporarily be lowered.

The unpredictable policies have knock-on effects across the economy.

Cynde Stewart, president of Arlington, Texas-based Raz Imports, said the company had to lay off some workers and furlough others after pausing production and shipping in April. The company, a wholesaler for seasonal decorations that imports heavily from China, usually ships the bulk of its Christmas goods right after the Fourth of July. Even though it has restarted the process now, Stewart knows the company is behind schedule.

“Our customer is just not going to be able to set their store as quickly,” she said.

That trend persisted across much of the U.S., sending renewed shock waves of disquietude among importers and the cargo transportation industry, and leaving business owners with more questions than answers.

U.S. and Chinese officials met twice over recent weeks to hammer out the framework for a trade war truce, which resulted in a 90-day pause of the highest tariff rates. Now some importers have been rushing to get their goods into the country before the deadline passes. And data shows that rates to ship containers have been climbing.

Levine, from the research firm Freightos, said he saw built-up demand in early June after the spring slowdown.

It’s unclear if this apparent uptick in activity will continue. The conditional trade agreement with China has been tenuous and faced several challenges already.

Stewart is optimistic the goods needed for the Christmas season will make it on time, but the uncertainty has made it difficult and stressful to do business.

“You have no idea what tomorrow brings,” Stewart said. “And you have no idea what happens after that grace period is over.”