where did this hurricane originate?
It is believed to have originated from a tropical wave which moved off the west coast of Africa and emerged into the Atlantic Ocean.
1900 Galveston hurricane
The storm is believed to have originated from a tropical wave which moved off the west coast of Africa and emerged into the Atlantic Ocean. 
how does the galveston hurricane of 1900 rank among all hurricanes to hit the u.s It was the deadliest natural disaster in United States history and the fourth-deadliest Atlantic hurricane.
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1900 Galveston hurricane [SEP] Meteorological history
The storm is believed to have originated from a tropical wave which moved off the west coast of Africa and emerged into the Atlantic Ocean. However, this is not completely certain because of the limited observational methods available to contemporary meteorologists, with ship reports being the only reliable tool for observing hurricanes. The first formal sighting of the tropical storm occurred on August 27, about east of the Windward Islands, when a ship encountered an area of unsettled weather. Over the next couple of days, the system moved west-northwestwards and is thought to have maintained its intensity as a weak tropical storm, before it passed through the Leeward Islands and entered the Caribbean Sea on August 31.