Executives at Columbia Sportswear in Portland, Ore., were in a high-level meeting last Friday to wrap up their response to the Trump administration’s latest round of tariffs on Chinese imports when the president took to Twitter.

American companies, President Trump posted not long after Columbia’s session had started, were “hereby ordered to immediately start looking for an alternative to China.” Hours later, Mr. Trump said he was raising tariffs even higher.

The plan under discussion by Columbia, which makes a variety of outdoor goods in China, like jackets and hiking shoes, had taken thousands of hours to draft, and it included shifting product lines to other countries and raising prices on others when the tariffs took effect in September.

“We had a solution, where we’re going to raise prices, where we’re going to move stuff,” said Tim Boyle, Columbia’s chief executive, who had called into the meeting from a vacation in Canada. “And then, an hour later, we learn he’s going to raise tariffs even further. It’s insane.”