Inflation spiked to 3.8% last month, according to the April Consumer Price Index, released on Tuesday. It’s the sharpest reading consumers have seen in three years, since Russia invaded Ukraine, spiking fuel prices and sending inflation to 4% in 2023.

But unlike the massive spike of that crisis—which hit quickly and broadly, igniting inflation across nearly two-thirds of the CPI basket almost overnight—this oil shock has a more pernicious nature. For one, it’s been slower to hit: crude markets have defied experts’ prognostications of doom as traders steadily rebalanced and tried to “look through” the crisis. Oil has stayed well below the $150 price hikes that some had imagined just weeks earlier, when oil markets were first rocked by the effective closure of the Strait of Hormuz thanks to the outbreak of the Iran war.

Still, gasoline is up 28.4% over the year, Tuesday’s inflation data showed, and 5.4% just on the month. Fuel oil is up 54.3% year-over-year. And unlike the Russia-Ukraine-driven energy crisis, this is “more than just an energy crisis,” said Diane Swonk, chief economist at KPMG.

“It is a supply chain disruption, and that’s important—and you’re only beginning to see the effects,” Swonk told Fortune.

She added that accelerating food prices—grocery prices climbed 0.7% in April—mean the shortage of diesel, a critical fuel for agricultural equipment and shipping vessels, is beginning to pass through almost exactly on schedule.

“Diesel hits everything. It hits shipping costs. There are very low margins,” she said. “We knew the spillover effects from the war in Iran would hit within four to six weeks. And there you got it, in April.”

Computers and electronics are climbing too, Swonk noted, but for a separate reason: memory chip shortages tied to the AI buildout, which she said will “only worsen” as supply chains tighten for inputs like helium. The tipping point comes “later this year,” she said. Meanwhile, the electricity number—up 2.1% in a single month—is the AI data center load showing up on consumer bills.

“It’s intensifying the backlash that we’re seeing growing towards data center construction at the state and local level,” Swonk added. “In particular, it’ll be on the ballot in November.”

The print arrives weeks before Kevin Warsh is set to take over as Fed chair, where the “dual mandate” of full employment and keeping inflation below 2% will be incumbent on him. Swonk did not envy the handoff.

“It’s not something I wish on anyone in central banking,” she said. “There are no easy options.”

The trouble is that the labor market looks better on paper than it feels to most Americans, particularly the youngest ones. If the Fed tries to hike rates to stave off inflation, it risks damaging an already vulnerable labor market. If it cuts rates or stays on pause to give the labor market room to strengthen, it risks stoking a more persistent bout of higher prices.

“That is a no-win situation for someone coming in at the helm of the Federal Reserve in a year where affordability is already getting worse instead of better,” Swonk said.

There were some softer points in the CPI report. The cost of new vehicles fell 0.2%, and medical care commodities dropped 0.4%. Used cars were flat after months of declines. Swonk attributed some of the goods softness to demand destruction—when prices stay too high for too long and people shift away.

“It gets to the inequality problem too, because affluent buyers can support and absorb those shocks much more than low-income households—but many of those services seep into what low-income households have to pay,” Swonk said.

Brian Mulberry, chief market strategist at Zacks Investment Management, agreed, pointing to the soft used-car and medical-care prints as “very early” signs of consumers pulling back on discretionary spending — a pattern that, if it holds through the summer, would be “a bearish signal that rates will not move lower as the market had expected.”

Other forecasters were somewhat more sanguine. Oxford Economics lead US economist Bernard Yaros wrote that tariff effects and energy passthrough were “evident in the core measure, but there was also significant noise,” and kept his call for the Fed to remain on pause through year-end.

Markets, having long ignored the Iran war, dipped a little on Tuesday after the report. The 10-year Treasury yield moved past 4.43% on the print.

For Swonk, the bottom line was simpler.

“It’s a miserable number,” she said. “There’s just no other more regressive tax on consumers than inflation.”