Fast-growing fires were responsible for nearly 90% of fire-related damages despite being relatively rare in the United States between 2001-2020, according to a new study led by the University of Colorado Boulder. "Fast fires," which thrust embers into the air ahead of rapidly advancing flames, can ignite homes before emergency responders are able to intervene. The work, published today in Science, shows these fires are getting faster in the Western U.S., increasing the risk for millions of people.