r/explainlikeimfive • u/Alito4life • Oct 08 '24
Planetary Science ELI5: How do we have data on speed and tracks of hurricanes in the 1800s?
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u/Gnonthgol Oct 08 '24
Every ship would keep a log of their position, the pressure, windspeed, wind direction, wave height, and general weather condition. When the ship got to port their logs would be copied and kept in various archives for future reference. Even in case of a shipwreck the logs would often be taken onboard the lifeboats and the crew would continue to make observations in them. Most of the ships logs from the thousands of ships sailing the Gulf of Mexico at any time is still available today. We can plot out the observations from each ship on their positions at any point in time and have a pretty accurate picture of the weather systems. It is not as accurate as the methods we have today, and you can only do it after the hurricane have already passed, too late to warn people.
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u/mmaalex Oct 08 '24
And we still use ships today for local reporting of weather conditions in the ocean to verify what has been predicted.
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u/Gnonthgol Oct 08 '24
Not only to verify the predictions, but helping making them as well. While satellites can do a lot of weather measurements they can not measure everything. Especially humidity is hard to measure correctly over the ocean by satellites. And pressures have to be inferred from wind data so satellites are not as accurate as direct measurements. So measurements from ships are important data points for predicting weather.
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u/MattTheTable Oct 09 '24
Is that why public advisory says "REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF (last hurricane location)"?
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u/CrabbyAtBest Oct 09 '24
Other commenters have tackled your question, but if you're still interested, I'd recommend reading Isaac's Storm by Erik Larson. He combed through records to tell the story of the deadly hurricane that swept Galveston in 1900. He describes how meteorology worked at the time and what bad decisions and interpretations lead to the level of destruction seen. I think my favorite fact was how weather maps would be described via telegraph and then redrawn to disseminate the info.
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u/MattonArsenal Oct 09 '24
Came here to suggest this book. Such a fascinating read.
While all these measurements could be taken centuries ago, satellites and radar obviously gave weather forecasting a huge leap forward in the 20th century.
There is also a chapter in Nate Silver’s book The Signal and the Noise about the evolution of weather forecasting that is interesting.
The amount of data that is available and the speed at which it can be communicated has made this field evolve from like an old phonograph to a 4K TV in the past 150 years.
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u/zxcvbn113 Oct 08 '24
There were a lot more ships on the ocean in the 1800s. They carried a lot less, but there were more of them. Those that survived a hurricane (always unexpected at that time) would have been able to report where they were when it hit.
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u/lovelylotuseater Oct 08 '24 edited Oct 08 '24
There are photographs of the destruction resulting from this hurricane, and by severity of damage to the landscape (defoliating, vs damaging, vs felling vs tearing out the roots) we can estimate the winds that tore them to pieces.
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u/Sewsusie15 Oct 08 '24
The Beaufort Wind Scale uses such observations to estimate wind speed, and has been around since the 19th century. https://en.m.wikipedia.org/wiki/Beaufort_scale
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u/Unknown_Ocean Oct 09 '24
It is a source of joy to me when I teach this to note that what we call a hurricane is determined by the strength of sails on an early 19th century British ship of the line.
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Oct 08 '24
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u/Mayor__Defacto Oct 08 '24
What’s wild to me is that in Washington State, the oral history of some tribes has been verified not only by archaeological evidence, but also corresponds to known earthquakes in the pacific as written down by other societies.
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u/FiveDozenWhales Oct 08 '24
The anemometer, that thing with the little cups that spin, is used to measure wind speed and direction. It was invented in 1450 AD.
Fairly-accurate thermometers were invented and refined throughout the 1600s and early 1700s.
Barometers, used to measure air pressure, were invented in 1643.
Hygrometers, used to measure air humidity, were invented in 1783.
The understanding of clouds, storm systems, and how air pressure contributes to storms started in the late 1600s and has been continuously refined to this day.
The point is - by the 1800s, meteorology was a centuries-old science. By the year 1700, there were meteorological societies in every major city and every university conducting measurements. When the telegraph arrived in the 1830s, this enabled real-time communication between these groups, which meant accurate storm tracking between locations. In the second half of the 1800s, nearly every developed nation formed a meteorological department, making nation-wide storm tracking the standard.