As housing data rolls in for April and May, it tells us the housing market’s unprecedented acceleration—which saw a record 20.6% year-over-year jump in U.S. home prices between March 2021 and March 2022—is either on pause or over. In the coming months, don’t get confused by lagging home price data: All signs point to a slowdown in the rate of home price growth. At Fortune, we’ve dubbed this shift the Great Deceleration.

The driving force behind the Great Deceleration is the Federal Reserve. Over the past six months, the average 30-year fixed mortgage rate has spiked from 3.11% to 5.09% as the Fed has moved into inflation-fighting mode. Of course, that not only prices out some would-be buyers, but also sees some borrowers—who must meet lenders’ strict debt-to-income ratios—lose their mortgage eligibility altogether.

The biggest indication of cooling comes from the housing market’s premier leading indicator: inventory. The pandemic’s housing boom saw inventory—the number of unsold listings—fall to four-decade lows. By March, nationwide inventory levels on Zillow were 64% below March 2019 levels. But as mortgage rates approached 5% this spring, inventory levels began to rise again. Indeed, between March 26 and May 7, nationwide inventory levels rose 10%.

“For me, the best part of the housing story in 2022 is the rise of inventory, as this will put home sellers and builders in check. They had too much pricing power and they pushed prices way too high,” says Logan Mohtashami, lead analyst at HousingWire.

Heading into 2022, Mohtashami was already on the higher mortgage rate bandwagon. In his mind, it was the only way to rein in “the savagely unhealthy” housing market. The logic: As home shoppers temporarily delay their purchase in the face of rising rates, that gives inventory the breathing room it needs to rise. When those buyers reenter the market, in theory, they return to find inventory higher and feel less pressure to overbid.

“I am hoping that higher rates do their thing and create more balance,” Mohtashami says.

Back on March 23, Fortune labeled soaring mortgage rates a clear economic shock to the housing market. Soon afterward, inventory finally started to rise. That only picked up steam through April. In all, 83% of the nation’s 400 largest housing markets saw inventory levels rise over the most recent six-week window. The biggest jumps in inventory were in Coeur d’Alene, Idaho (54%); Reno (49.6%); Bend, Ore. (48.7%); Flagstaff, Ariz. (48.5%); and Manchester, N.H. (46.4%).

But homebuyers shouldn’t get too excited—yet.

While inventory levels are rising fast percentage wise, they're still far below pre-pandemic levels. Look no further than Coeur d’Alene, which saw inventory spike 54% between late March and early May as it went from 242 to 373 active listings. However, that's still 62% below the 980 listings it had the first week of May 2019. Simply put: Even if the Great Deceleration picks up steam, it will take time before we’re back to a pre-pandemic housing market.

“The housing market is still savagely unhealthy because [of low] total inventory levels in America,” Mohtashami says. In order for us to return to a "normal" housing market, his economic models show we need to see national inventory rise to a range between 1.52 million to 1.93 million units. The National Association of Realtors’ latest reading has inventory at just 1.03 million units.

Heading forward, Mohtashami’s biggest fear is that mortgage rates begin to fall again and the momentum is lost. If that happens, the Great Deceleration could get put on pause.

“While I am very encouraged that inventory is rising on a year-over-year basis, we need it to stick and head a lot higher. My concern in the future is if the rates fall again, some of the inventory gains we had will go away,” Mohtashami says.

If you’re hungry for more housing data, follow me on Twitter at @NewsLambert.