Wildfires increase flood risk by making it harder for soil to absorb water. We studied how this risk changes over time as the landscape recovers and how it will be affected by more intense rainfall due to climate change. Using a computer model of a burned watershed in Arizona, we found that while the soil's ability to soak up water recovers over a few years, future rainfall is predicted to be so intense that the period of high flood danger will last longer, making severe floods much more common.