TNB Night Owl – The Great Molasses Flood

There are key disasters in American history, where “Great” is deemed necessary to indicate scale.  The Great San Francisco Earthquake.  The Great Chicago Fire.

The Great Molasses Flood.

When discussing disasters, floods are often mentioned, but they’re usually considered in the context of slowly rising water levels, such as in the recent Houston flooding.  Or “flash floods”, large amounts of rainwater channeled through a path at the base of hills or mountains.  They usually aren’t talking about rushing walls of fluid smashing through the streets of large cities, unless they’re discussing Boston.


The source of what became known as the “Great Molasses Flood” was a 50-foot-tall steel holding tank located on Commercial Street in Boston’s North End. Its sugary-sweet contents were the property of United States Industrial Alcohol, which took regular shipments of molasses from the Caribbean and used them to produce alcohol for liquor and munitions manufacturing. The company had built the tank in 1915, when World War I had increased demand for industrial alcohol, but the construction process had been rushed and haphazard. The container started to groan and peel, and it often leaked molasses onto the street. At least one USIA employee warned his bosses that it was structurally unsound, yet outside of re-caulking it, the company took little action.

It wasn’t just that the tank was fifty feet tall.  It was also 90 feet in diameter, with a capacity of more than two million gallons of molasses.  It rested toward the top of a small hill on Commercial street.  On January 15, 1919, the tank was nearly full, the day was unseasonably warm… and as some of the molasses fermented in the heat, gases were released that increased the internal pressure.

The tank blew.  And with it came disaster history.

A 40-foot wave of molasses came thundering down Commercial street, propelled by gravity and channeled by the buildings that lined the street.  Buildings and vehicles were destroyed as the thick fluid smashed into them with greater force than less-dense water would have produced.  Worse was the effect on people and animals.  From Scientific American:

Consider non-Newtonian fluids such as toothpaste, ketchup and whipped cream. In a stationary bottle, these fluids are thick and goopy and do not shift much if you tilt the container this way and that. When you squeeze or smack the bottle, however, applying stress and increasing the shear rate, the fluids suddenly flow. Because of this physical property, a wave of molasses is even more devastating than a typical tsunami. In 1919 the dense wall of syrup surging from its collapsed tank initially moved fast enough to sweep people up and demolish buildings, only to settle into a more gelatinous state that kept people trapped.

The viscosity of the fluid is great enough that it also prevents actions such as swimming; the additional energy required to move an arm through the syrup simply moved more syrup into place.  Only by moving into another medium such as air or water could any standard motion be resumed.  Many who were knocked down into a few feet of the molasses were unable to get free without aid… and even then, only if their heads weren’t covered.

In the end, 21 people died, more than 150 others were injured, and many horses were killed by giant molasses wave; dozens of buildings were destroyed; and the cleanup efforts were herculean.  Boston had ridden the wave into bizarre disaster history.

Question of the night: What’s your favorite cookie type?  (Bonus points if you can honestly say it’s molasses.)

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About AlienMotives 1991 Articles
Ex-Navy Reactor Operator turned bookseller. Father of an amazing girl and husband to an amazing wife. Tired of willful political blindness, but never tired of politics. Hopeful for the future.

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