When weather catastrophes hit, the big-ticket damages tend to come not from heat waves but from floods, hurricanes, and wildfires. Natural disasters caused billions of dollars in damagelast month alone, according to a recent report, from Canadian wildfires ($3.1 billion), to European flooding ($4.6 billion), to U.S. storm damage ($1 billion). The economic loss from 300 Indian heatwave deaths in April however …