Over the past few decades, wildfires in the western U.S. have grown more frequent and burned more land.

A new paper in the journal PNAS describes how wildfires in the west can intensify thunderstorms in the central U.S.

Computer models of California and Oregon wildfires reveal the forces at work: heat and airborne particles raise pressure near the surface, bolster westerly and southwesterly winds, ramp up wind shear and deliver more moisture and particles to the country’s heartland.

The result: 39% more heavy precipitation, including 34% more severe hail events.

The authors say predicted growth in western wildfire frequency and intensity may increase these downwind effects.