Tropical Storm Harvey has dropped more than 11 trillion gallons of water on Texas, triggering catastrophic, unprecedented flooding in the Houston area. The rains have broken all-time records, exceeding the rainfall totals seen during Tropical Storm Allison in 2001. There may be no parallel available to any other rainstorm in U.S. history, based on the number of people affected, amount of water involved, and other factors, meteorologists have warned. Due to its wide geographic scope across America’s 4th-largest city, the ensuing flood disaster may rank as one of the most, if not the most, expensive natural disaster in U.S. history.
http://mashable.com/2017/08/27/harvey-dumps-11-trillion-gallons-water-houston-flood/#GfqI6s2UMaqk
