I happened across this in my morning reading, entirely by accident. On January 15th, 1919, an enormous molasses storage tank burst, spewing 2.5 million gallons of molasses into the streets of a Boston neighborhood. This created an 8 to 15 foot high wave of molasses, moving at about 35 miles per hour. It killed 21 people and injured over 150 more; there was a large amount of property damaged (including buildings and railroad).
And I thought I knew my U.S. history fairly well!