The One Minute Geographer: The Great Plains — the 20 inch Rainfall Line

The 100th meridian in yellow; rainfall — red; elevation — blue; and grasslands — green. Base map from whatsansweer.com; lines drawn by the author.

The 100th Meridian (yellow on the map), is a fascinating line because it happens to closely coincide with other important geographical features of the Great Plains.

Today we’ll take a quick look at the 20-inch rainfall line in red, above. I drew it to roughly correspond with the 20-inch line on the map of annual precipitation below.