Falling trees and tree fragments are one of the top five causes of fatalities for wildland fire responders. In six out of ten recent years, at least one fatality from a tree strike has occurred while a fire responder was on duty, and others were injured. We used TreeMap, a national map of forest characteristics, including individual tree height, diameter, and status (live or dead), to generate a map of snag hazard for forested areas of the continental U.S. at 30 x 30 m resolution. Snag hazard was classified into categories of low, moderate, high, or extreme based on snag density and height. Within-class accuracy was as high at 86%, suggesting that the Snag Hazard map can help wildland fire managers identify and avoid exposing fire responders to hazardous conditions. Accuracy was higher outside recently disturbed areas (88%) than inside (79%), perhaps reflecting strong spatial patterns and heterogeneity of mortality within disturbed areas. The Snag Hazard map is a frequently requested product from the Forest Service's Risk Management Assistance Group. The goal of RMA is to provide analytics to decision makers and fire leadership to facilitate risk-informed decision-making to improve safety, effectiveness, and outcomes. We present a case study showing how the Snag Hazard 2016 map was used to inform fire responders during an active wildfire incident in California during the 2020 fire season.