What is the worst natural disaster, in terms of lives lost, to occur on U.S. soil?

Few things capture the hearts and minds of Americans more than disasters - and in a YouTube age where pictures and cameras are ubiquitous, this tendency has only grown.  The history of America is certainly replete with natural disasters, so its only fair that we included at least one question on the powerful subject.  This question comes off of our Pocket Trivia: US History game - What is the worst natural disaster, in terms of lives lost, to occur on U.S. soil?  Is it Hurricane Katrina, the San Francisco Earthquake of 1906, the Okeechobee Hurricane or the 1900 Galveston Hurricane?

Believe it or not, it is not Hurricane Katrina - a confirmed 1,836 people died as a direct or indirect result of Katrina, but it is not the "leader" in terms of all-time deaths. 

Not the San Francisco Earthquake of 1906 - over 3,000 people died there, however, and it is the worst natural disaster in California history.

The Okeechobee Hurricane of 1928 killed 300 people and was the 2nd Category Five hurricane to ever be recorded - but it is not the worst in terms of death toll.

No, that "honor" belongs to the 1900 Galveston Hurricane.  This hurricane killed between 6,000 - 12,000 and utterly destroyed the city of Galveston.  The city was close to sea level and was hits with winds of over 100 mph (though that estimate is likely low, as the weather bureau's low as the weather bureau's measurement tools were blown away in the storm).  Thankfully, this record has stood for over 100 years.  Here's to hoping it won't be broken!