The most intense hurricanes as measured by minimum central pressure are not necessarily the deadliest or costliest storms. In most cases, the amount of damage caused by a hurricane does not only depend on its intensity but also on the amount and value of property at risk in the storm’s path. Much of the damage caused by the costliest hurricanes was caused by inland flooding triggered by torrential rain. Many of the deadliest and most expensive hurricanes made landfall in states along the Gulf Coast, where the infrastructure and economies of major cities are based on proximity to oceans and rivers.
Many of the largest hurricane death tolls resulted from storm surges that caused the ocean level to rise 10 feet or higher. In the Great Galveston Hurricane in 1900, the deadliest tropical cyclone in U.S. history, a storm surge covered all of Galveston Island off the Texas Gulf Coast in 8 to 12 feet of water, destroying nearly all buildings in the vicinity and leading to the deaths of possibly 8,000 people by drowning or being crushed by debris.
While hurricanes may be growing more intense and frequent, disaster preparedness also is becoming more effective. Hurricane forecasting has advanced considerably over the last century and advanced warning has helped minimize the deadliness of many of the most powerful storms of the last several decades. Excluding 2005 — the year Hurricane Katrina directly killed about 1,200 people — the 10 years with the highest hurricane-caused death counts are all before 1960. Excluding Katrina, NOAA has reported 1,300 deaths caused by hurricanes since 1960, compared with 14,645 deaths reported between 1900 and 1960.
While hurricanes are becoming less deadly as damage mitigation strategies and disaster preparedness improve, they are also becoming more destructive. The 10 costliest hurricanes have all occurred since 1992. This may be partially because of the increased amount of property at risk today in comparison with previous decades. Adjusted for inflation, the costliest hurricanes in U.S. history were Hurricane Katrina in 2005, Hurricanes Harvey and Irma in 2017, Hurricane Andrew in 1992, and Hurricane Ike in 2008.
Tropical cyclone activity in the Atlantic Ocean often peaks in the late summer, when the temperature differences between the wind and sea surface are the greatest. Of the 70 most intense hurricanes since 1851, 63 occurred in August, September, or October.
To identify the most powerful hurricanes, 24/7 Wall St. reviewed the National Oceanic and Atmospheric Administration’s hurricane database (HURDAT 2), which tracks the date, time, location, minimum pressure (in millibars) and wind data for hurricane episodes from 1851 to 2017. Hurricanes were ranked according to their minimum pressure in millibars, where one millibar is the equivalent of 100 pascals in pressure. The lower a storm’s minimum pressure, the stronger the storm is. For context, air pressure is 1,013 millibars at sea level.