The Pacific Coastal Ranges
The most western of the physical regions of the conterminous United States is made up of the Pacific coast mountain ranges. Like the Rockies, they extend from Canada in the north to the border with Mexico in the south. The area is about 322 kilometers wide from east to west. It has some of the highest mountains as well as some of the richest farmland in the United States.
The interior range includes the Cascade Mountains in Washington and Oregon and the Sierra Nevada in California. Within the Sierra Nevada is Mount Whitney at 4,418 meters. Mount Rainier at 4,392 meters above sea level, is in the Cascade Range. Also in the Cascades are active volcanic peaks. Mount Helens erupted several times in recent years. Closer to the Pacific coast is a second range of mountains stretching from Washington to California.
Climate
The United States has areas of all five major climate groups.
Southern Florida has a tropical moist climate. Even in the coldest month of January, temperatures average above 21 degrees centigrade. The area has a growing season that lasts all year long.
North of the Ohio River and east of the Great Plains, there is a moist, cold winter climate. South of the Great Lakes, summers are hot and winters have at least one month of average high temperatures below 0 degree centigrate. East and West of the Great Lakes, summers are cooler and winters are longer.
Most of the Great Plains is under a semiarid climate. Rainfall averages only 20 to 51 centimeters a year. The Rocky Mountains block moisture from the west. Summers are very hot and winters are very cold on the plains. The range of temperatures is greater here than anywhere else in the country.
From the Rocky Mountains to the Pacific Coast, there are several small areas of similar climate broken up by the mountains. The highest parts of the Rockies are cold all year.
Basins in the intermontane region have a generally dry climate. This climate is found in parts of Nevada, Arizona, and New Mexico as well as in western Texas and southeastern California. Summers are generally hot with cold winters.
The Pacific Coast is under mostly moist mild winter climates of two kinds. The coastal mountains of northern California, Oregon, and Washington cause warm winds blowing in from the Pacific to dump their moisture over these three states. These lowland coastal areas have a midlatitude marine climate.
In central and southern California, there is a Mediterranean climate. Summers are dry and winters are cool and rainy.
The climate of Alaska is generally cold over the whole state. The Yukon River valley has a moist, cold winter climate of the subarctic variety. Along the southern coast of Alaska, temperatures are milder than in the Yukon Valley. North of the Brooks Range is the only area of polar climate in the United States.
The climate of Hawaii is tropical and moist. It receives short periods of rain throughout the year. There are, however, small variations. Some areas near the coast are drier while highlands are very wet. Mt. Waialeale, on the island of Kauai, is one of the wettest spots in the world.
Rivers and Lakes
The Mississippi River, along with its tributary, the Missouri, is one of the world's longest rivers. It flows from the Rocky Mountains for nearly 6,437 kilometers to the Gulf of Mexico. One of its folk names is "father of waters. The Ohio River is another major tributary of the Mississippi together with the Arkansas River and the Red River.
Like the Mississippi, the many shorter rivers that rise east of the Appalachian Mountains empty into the Atlantic Ocean. Among them are the Hudson River, the Delaware and the Potomac.
Three great river systems drain the region west of the Rocky Mountains. They empty into the Pacific Ocean. In the north, the Columbia River and its chief tributary, the Snake River, which drains part of Idaho, Washington and Oregon. The Sacramento and its main tributary, the San Joaquin, drain much of central and northern California. The Colorado River and its many branches drain much of southwestern United States. These three river systems have great value as sources for irrigation and hydroelectric power
The Rio Grande, about 3,200 kilometers long, forms a natural boundary between Mexico and the United States and is an important source of irrigation projects to the benefit of both countries.
The Yukon River in the north rises in the Canadian Rockies flows westward across Alaska and empties into the Bering Sea.
North America has more lakes by far than any other continent. The largest of these are the Great Lakes. They are the greatest collection of fresh water lakes in the world. Their total area is 245 thousand square kilometers. Lakes Superior, Huron, Erie, and Ontario form a natural border between northeastern United States and Canada. Only Lake Michigan lies entirely inside the United States. Lake Superior is the largest of the Great Lakes. It is about 563 kilometers long and 257 kilometers wide. The Great Lakes together with the Between LakeErie and Lake Ontario, on the Niagara River, which connects the two lakes, are the Niagara Falls, one of the natural wonders of the world, where the waters of the Niagara River precipitate from the height of 50 meters.
Another large group of lakes lies west of the Rockies. The most famous of these lakes are the Great Salt Lake, in Utah, and the Salton Sea lies about 80 meters below sea level in Southern California.
Mineral resources.
In resources of coal and natural gas, tungsten and molybdenum, lead and phosphorus the United States holds the first place in the world. In resources of copper, zinc and sulphur - the second. In resources of gold, silver, uranium, mercury and asbestos - the third. The United States is rich in oil, iron ore, various metallic ores. At the same time the country lacks a sufficient supply of some of the minerals required for modern industries. These must be imported into the United States. They include tin, nickel, manganese, chrome, cobalt, industrial diamonds.
The principal deposits of high-grade coals are concentrated in the eastern part of the country. The main producing areas are in the Appalachian region. Some other less important coal basins are to be found in the middle reaches of the Mississippi, in the north of the Great Plains and in the Rocky Mountains.
The chief oil-bearing area is in the southern part of the Interior Plains and the Gulf Coastal Plain. Other important oil fields are situated in the Pacific southwest (California) and the Rocky Mountains (Wyoming). Extensive oil-bearing areas have been discovered in the northern part of the Great Plains. Alaska is rich in oil and its resources are also tapped. Closely connected with oilfields are the vast deposits of natural gas (8 trillion cubic metres). However, the home resources of oil are insufficient, therefore the country is a major importer of oil from different countries of the world.
The chief deposits of iron ore are concentrated in the the region of Lake Superior. There are some deposits of iron ore in the south of the Appalachians, Birmingham, but the ores of this region are of a poorer quality, having a lower iron content.
Pittsburg, in the heart of coal-fields, was the first of the great steel cities, because it was cheaper to bring the ore to the coal than the coal to the ore. Today, the Pittsburgh area still produces about one-fifth of the nation's steel, and also supplies coal to the other great steelmaking centres - Chicago, Detroit, Cleveland, Buffalo.
Large deposits of non-ferrous metals are to be found mostly on the territory to the west of the Mississippi River - zinc, copper, lead and others. Principal resources of such metals as gold, silver and rare elements are in the Cordilleras. The main deposits of uranium are in New Mexico. In the total resources of uranium die United States is after the South African Republic and Canada.
As a whole, the United States has considerable resources of mineral raw materials for the development of industry. It is self-sufficient in coal, copper, lead, phosphate, molybdenum and some others.
In terms of costs oil, coal, natural gas, uranium consitute nearly 89 per cent of the total output of the extracting industry of the United States. Iron ore and copper constitute three-fourths of the cost of all the extracted metals.