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NOAA's Heritage Success Stories
Lewis and Clark: Pioneers in Meteorology, Too
 Mean and range of daily minimum temperatures recorded over the periods of record at modern weather stations in South Dakota, North Dakota, Montana, and Idaho, for relevant times of year along the expedition route, along with Lewis and Clark's daily sunrise data (black). Lewis and Clark's instrumental observations begin in 1804 on September 19 (day 262, right side) and they end when their last thermoment broke in 1805. Data from modern stations at elevations greater than 4000 feet are shown in green, while others are in red. (Click on graph for larger version.) |
Scientific studies can now show that the meteorological data recorded by Meriwether Lewis and William Clark during their epic journey across America in 1804-1805 are worthy of national admiration and celebration. While the primary goal of the mission as described by then-President Jefferson to the Congress was economic and strategic, both Jefferson and co-captains Lewis and Clark showed interest in and capacity for scientific understanding of the meteorology of the then-unknown West. Jefferson's instructions to Lewis called for observations of "climate, as characterized by the thermometer, by the proportion of rainy, cloudy, and clear days, by lightning, hail, snow, ice, by the access & recess of frost, by the winds prevailing at different seasons..." Lewis and Clark followed Jefferson's instructions to the letter to become the first systematic weather observers who travelled through the American West.
NOAA scientists Susan Solomon and John Daniel compared Lewis and Clark's daily observations to many decades of modern data collected by the dedicated volunteers of the U.S. Cooperative Observer network at stations along their route. The comparisons illustrate that Lewis and Clark's observations of temperatures were apparently of very high quality. That was due to careful attention to the work, including the instrument calibrations meticulously performed by Lewis himself. Lewis and Clark and their men also documented typical spring and fall Western snows, flash floods, and warm Oregon winters -- familiar features of western climate that often surprised and occasionally plagued these men from the eastern seaboard.
In meteorology as in other subjects ranging from map-making to zoology, the passage of centuries has only shown more ways in which the expedition of Lewis and Clark was a triumph of its era.
To find out more, see Solomon, S., and J. S. Daniel, Lewis and Clark: Pioneering meteorological observers in the American West, Bulletin of the American Meteorological Society, volume 85, number 9, 1273-1288. 2004.
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