Much of California consists of a Mediterranean climate, with sometimes excessive rainfall from October–April and nearly no rain the rest of the year. In the Pacific Northwest rain falls year-round, but is much heavier during winter and spring. The mountains of the west receive abundant precipitation and very heavy snowfall. The Cascades are one of the snowiest places in the world, with some places averaging over 600 inches (1,524 cm) of snow annually, but the lower elevations closer to the coast receive very little snow. Another significant (but localized) weather effect islake-effect snow that falls south and east of the Great Lakes, especially in the hilly portions of the Upper Peninsula of Michigan and on the Tug Hil Plateau in New York. The lake effect dumped well over 5 feet (1.52 m) of snow in the area of Buffalo, New York throughout the 2006-2007 winter. The Wasatch Front and Wasatch Range inUtah can also receive significant lake effect accumulations from the Great Salt Lake.

Extremes

In northern Alaska, tundra and arctic conditions predominate, and the temperature has fallen as low as −80 °F (−62.2 °C). On the other end of the spectrum, Death Valley, California once reached 134 °F (56.7 °C), the second-highest temperature ever recorded on Earth.

On average, the mountains of the western states receive the highest levels of snowfall on Earth. The greatest annual snowfall level is at Mount Rainier in Washington, at 692 inches (1,758 cm); the record there was 1,122 inches (2,850 cm) in the winter of 1971–72. This record was broken by the Mt. Baker Ski Area in northwestern Washington which reported 1,140 inches (2,896 cm) of snowfall for the 1998-99 snowfall season. Other places with significant snowfall outside the Cascade Range are the Wasatch Mountains, near the Great Salt Lake, and theSierra Nevada, near Lake Tahoe. In the east, while snowfall does not approach western levels, the region near the Great Lakes and the mountains of the Northeast receive the most. Along the northwestern Pacific coast, rainfall is greater than anywhere else in the continental U.S., with Quinault Rainforest  in Washington having an average of 137 inches (348 cm). Hawaii receives even more, with 460 inches (1,168 cm) measured annually on Mount Waialeale, in Kauai. The Mojave Desert, in the southwest, is home to the driest locale in the U.S.Yuma, Arizona, has an average of 2.63 inches (6.7 cm) of precipitation each year.

In central portions of the U.S., tornadoes are more common than anywhere else on Earth and touch down most commonly in the spring and summer. Deadly and destructive hurricanes occur almost every year along the Atlantic seaboard and the Gulf of Mexico. The Appalachian region and the Midwest experience the worst floods, though virtually no area in the U.S. is immune to flooding. The Southwest has the worst droughts; one is thought to have lasted over 500 years and to have decimated the Anasazi people. The West is affected by large wildfires each year.

 

 

5. Natural disasters

The United States is affected by a variety of natural disasters yearly. Although drought is rare, it has occasionally caused major disruption, such as during the Dust Bowl (1931–1942). Farmland failed throughout the Plains, entire regions were virtually depopulated, and dust storms ravaged the land.

 Tornadoes and Hurricanes

The Great Plains and Midwest, due to the contrasting air masses, sees frequent severe thunderstorms and tornado outbreaks during spring and summer with around 1,000 tornadoes occurring each year. The strip of land from north Texas north to Kansas and east into Tennessee is known as Tornado Alley, where many houses have tornado shelters and many towns have tornado sirens. Another natural disaster that frequents the country are hurricanes, which can hit anywhere along the Gulf Coast or the Atlantic Coast as well as Hawaii in the Pacific Ocean. Particularly at risk are the central and southern Texas coasts, the area from southeastern Louisiana east to the Florida Panhandle, the east coast of  Florida, and the Outer Banks of North Carolina, although any portion of the coast could be struck. Hurricane season runs from June 1 to November 30, with a peak from mid-August through early October. Some of the more devastating hurricanes have included the Galveston Hurricane of 1900, Hurricane Andrew in 1992, and Hurricane Katrina in 2005. The remnants of tropical cyclones from the Eastern Pacific also occasionally impact the western United States, bringing moderate to heavy rainfall.

Flooding

Occasional severe flooding is experienced. There was the Great Mississippi Flood of 1927, the Great Flood of 1993, and widespread flooding and mudslides caused by the 1982-1983 El Niño event in the western United States. Localized flooding can, however, occur anywhere, and mudslides from heavy rain can cause problems in any mountainous area, particularly the Southwest. Large stretches of desert shrub in the west can fuel the spread of wildfires. The narrow canyons of many mountain areas in the west and severe thunderstorm activity during the monsoon season in summer leads to sometimes devastating flash floods as well, while Nor'Easter snowstorms can bring activity to a halt throughout the Northeast (although heavy snowstorms can occur almost anywhere).

Geologic

The West Coast of the continental United States and areas of Alaska (including the Aleutian Islands, the Alaskan Peninsula and southern Alaskan coast) make up part of the Pacific Ring of Fire, an area of heavy tectonic and volcanic activity that is the source of 90% of the world's earthquakes. The American Northwest sees the highest concentration of active volcanoes in the United States, in Washington,Oregon and northern California along the Cascade Mountains. There are several active volcanoes located in the islands of Hawaii, including Kilauea in ongoing eruption since 1983, but they do not typically adversely affect the inhabitants of the islands. There has not been a major life-threatening eruption on the Hawaiian islands since the 17th century. Volcanic eruptions can occasionally be devastating, such as in the1980 eruption of Mount St. Helens in Washington.

The Ring of Fire makes California and southern Alaska particularly vulnerable to earthquakes. Earthquakes can cause extensive damage, such as the 1906 San Francisco Earthquake or the 1964 Good Friday Earthquake near Anchorage, Alaska. California is well known for seismic activity, and requires large structures to be earthquake resistant to minimize loss of life and property. Outside of devastating earthquakes, California experiences minor earthquakes on a regular basis.

Other Natural Disasters

Other natural disasters include: tsunamis around Pacific Basin, mud slides in California, and forest fires in the western half of the contiguous U.S. Although drought is relatively rare, it has occasionally caused major economic and social disruption, such as during the Dust Bowl(1931–1942), which resulted in widespread crop failures and duststorms, beginning in the southern Great Plains and reaching to the Atlantic Ocean.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6.Clossing part

USA is like a special world with its own live, its own land , its own language…….. 
Many of people living there is happy , and I think it is the best rate of the country.