NPS,JH-Anderson

Sunset at Astoria, Oregon

President Thomas Jefferson gave instructions to Meriwether Lewis and William Clark regarding most facets of the 1804 expedition into and across the North American continent. Of particular mention is his instruction for them to record,

“climate, as characterised by the thermometer, by the proportion of rainy, cloudy & clear days, by lightning, hail, snow, ice, by the access & recess of frost, by the winds prevailing at different seasons, the dates at which particular plants put forth or lose their fl ower, or leaf,times of appearance of particular birds, reptiles, or insects.”

What environmental conditions did Lewis and Clark expect to find along the Missouri River of the Great Plains and beyond? Were they expecting a tropical climate? A desert? A paradise of temperate weather, fertile ground and navigable waterways? Did they expect mighty snowpacks and torrential rain?

To find out more, read our brochure available for download entitled, "Experiencing Climate."