Natural gas is mostly methane. In my piece on the Cornell study, my subhed was âLeakage of methane from fracking boosts shale gas global warming impact.â I didnât note until several paragraphs later that âNatural gas is composed largely of methane,â which comes from the second sentence of the study itself.
Tornado strength is currently measured on what is called the Enhanced Fujita Scale (adapted from the simpler Fujita Scale in 2007), which gives the tornado a rating from 0 to 5 based on estimated wind speeds and the severity of the damage.
Overall, most tornadoes (around 77%) in the United States are considered weak (EF-0 or EF-1) and about 95% of all United States tornadoes are below EF-3 intensity. The remaining small percentage of tornadoes are categorized as violent (EF-3 and above).