What We Know About What Led to the L.A. Wildfires

Multiple fires continue to burn in the Los Angeles area after flames have razed neighborhoods, forced mass evacuations and claimed at least 27 lives over more than a week. Some fires have been contained, but three are still active.  That includes two of the biggest and most devastating infernos, the Palisades fire in West Los Angeles and the Eaton fire in Altadena, which are already projected to be the most costly in U.S. history. As the fires have spread, false or unsupported information about them — particularly about how they started and why they have been so severe — has also escalated. Some people have cast the fires as largely the result of global warming, while others have denied any climate change connection and pinned blame on a lack of water or vegetation management. (As we’ve& already written, many of the claims about water are bogus.) Meanwhile, some have baselessly pointed to lasers or directed energy weapons, among other fanciful conspiracies, as ignition sources. Here, we explain what’s known about how the fires started and the factors that scientists do — and don’t — think contributed. What conditions allowed for the rash of catastrophic fires? What sparked the fires? Did...