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Lewis & Clark National Historic Trailpeak of mount hood in oregon
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Lewis & Clark National Historic Trail
Climate Then and Now
 
Sunset at Astoria, Oregon

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."

Montana landscape off Rt. 275
Climate Change in National Parks
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William Clark's signature at Pompeys Pillar  

Did You Know?
Two hundred years after the Lewis and Clark Expedition, the only physical evidence of the journey is found near Billings, MT. In July 1805, William Clark carved his name into the soft rock of what he called Pompeys Tower. This site is now preserved at Pompeys Pillar National Monument.

Last Updated: September 28, 2009 at 14:39 EST