As the pandemic home buying frenzy comes to a halt, markets that saw overwhelming migration and home price increases are now experiencing an extreme decline in home sales. Sales in Boise are down 28% on a year-over-year basis as inventory levels begin to surge, now up 161%. Predicted to slide downward, the market’s home values and sales prices will take a hit.

How did markets like Boise and Phoenix get so bubbly? Ali Wolf, chief economist at Zonda, blames supply constraints in those markets. The demand influx—which the Federal Reserve pinpoints as the culprit of the Pandemic Housing Boom—simply overwhelmed supply in Western boomtowns. That saw bidding wars that took prices far beyond fundamentals.

“Many markets in the West are landlocked for one reason or another, whether [by] the ocean, mountains, national parks, or growth boundaries. As a result, building is more limited in these markets compared to parts of the country with less regulation and more developable land,” Wolf tells Fortune. “The strong demand over the past two years drove up home prices across the country and it appears the West hit the pricing ceiling quicker than other markets given the particular supply constraints.”