 On September 8 , 1900 , the island was struck by a devastating hurricane . This event holds the record as the United States ' deadliest natural disaster . The city was devastated , and an estimated 6 @,@ 000 to 8 @,@ 000 people on the island were killed . Following the storm , a 10 @-@ mile ( 16 km ) long , 17 foot ( 5 @.@ 2 m ) high seawall was constructed to protect the city from floods and hurricane storm surge . A team of engineers including Henry Martyn Robert ( Robert 's Rules of Order ) designed the plan to raise much of the existing city to a sufficient elevation behind a seawall so that confidence in the city could be maintained . 
