THE GREAT PLAINS

THE GREAT PLAINS

• Historical Perspectives of the Region– Spanish explorer Coronado explained, "this

region is the best I've seen for producing the crops of Spain - the land is flat, soil is black, and is well watered with springs and rivers.”

– Early 1800s - perceived to be wholly unfit for cultivation and uninhabitable for people depending on agriculture

– Mid 1850s - labeled the "Great American Desert."

GREAT PLAINS

PHYSICAL GEOGRAPHY• Terrain

Elevation rises gently from east to west (500 meters to 1500 meters).

Southern half of the region has unvaried topography

Northern half is more variable and is characterized by “badlands.” Very irregular topography resulting from wind and

water erosion of sedimentary rock. Widespread on the Missouri Plateau between

northern Nebraska and the Missouri River Best example in western South Dakota.

GREAT PLAINS

PHYSICAL GEOGRAPHY

• Vegetation Grasses are taller and more dense

in the East and shorter and relatively sparse in the West.

Much of the grasses have intricate root systems, which were difficult to plow and often required "Bonanza teams" of about 20 animals to break the sod.

PHYSICAL GEOGRAPHY

• Precipitation Most precipitation in the region results from

the interaction of air masses. Amounts vary from 10-40 inches annually,

decreasing from east to west. About 75% of the precipitation falls from

April through August. Major droughts have occurred in 20 year

cycles. Significant droughts in the 1890s, 1910s,

1930s, 1950s, and 1970s

PRECIPITATION VARIABILITY

PHYSICAL GEOGRAPHY

• Temperatures Region experiences extremes in

temperatures because of its continental climate

Fluctuations increase from south to north.

Northern Texas has over 240 frost free days each year, whereas Canada's prairies experience less than 90.

PHYSICAL GEOGRAPHY

• Winds- serve as a mixed blessing to the region. In late spring and summer, wind velocities

in the central and northern Plains are among the highest in North America. Ensures maximum efficiency for the region's windmills.

High rates of evaporation and transpiration may minimize the effects of precipitation.

WIND POWER“Certainty Rating of the Wind Resource”

PHYSICAL GEOGRAPHY

Chinooks - warm, dry, winter winds from the Pacific that bring welcomed relief during the winter months

Blizzards - characterized by snow, wind, & intense cold Occur when cold polar air masses push south along

the Rockies, and can last for several days Tornadoes - pose a significant regional hazard.

Great Plains experience far more tornadoes annually than any other comparable area in the world.

Parts of Texas, Oklahoma, and Kansas encounter 200 - 300 per year, largely concentrated in the spring and early summer.

TORNADO FREQUENCY

AGRICULTURE• Large scale and machinery intensive• Wheat

Winter wheat Grown from Northern Texas to Southern

Nebraska. Spring wheat

Areas with severe winters and cool summers Located from central South Dakota to the south

central Prairie Provinces of Canada. U.S. and Canada are the world's leading exporters Kansas and North Dakota lead all U.S.

production. Saskatchewan is by far Canada's largest

producer.

AGRICULTURE

• Shipment Patterns Most Canadian wheat goes to

Winnipeg then to Thunder Bay for shipment across the Great Lakes. In the West, it goes to Vancouver by rail and is then shipped by sea.

U.S. wheat shipments travel across the Great Lakes or down the Mississippi River.

AGRICULTURE

• Other Crops Barley - important in the Canadian

province of Alberta. Sorghum - used for stock feed and

grown throughout the hot, dry margins of the plains

Cotton - a dominant crop in Texas Oats - grown throughout the Northern

Plains area Cattle