Earthquakes in California, hurricanes in Florida, blizzards in New York, tornadoes in Kansas—Mother Nature has many options for wreaking havoc everywhere in the U.S. A comprehensive risk estimate for every type of natural disaster can help insurance underwriters decide how much to charge for covering structures against damage. But creating one is an enormous endeavor. The world’s biggest risk analysis and management company, Risk Management Solutions, has been developing this catastrophe risk map—the most comprehensive of its kind—since the early 1990s. Insurance companies are less concerned about hazards that affect sparsely developed areas. So instead of just calculating where a disaster might strike, analysts compute the likelihood—and likely severity—of property damage at a given location. The result is a single scale that reveals the scope of vulnerability—and most of our big cities are at risk.