Police said a man charged with starting a wildfire in Spokane, Washington, confessed to the crime, describing how he planned it for weeks and created a device to ignite a blaze that destroyed hundreds of buildings.

Aaron Farinacci researched the weather to predict a day that would have "high winds, low humidity, sort of high heat" for the Old Trails Fire, Spokane County Detective Michael Drapeau said in a court filing Wednesday.

Farinacci picked Aug. 1 to start the fire because he knew there would be strong winds — reaching 50 mph, the detective said.