The Rocky Mountains are the main chain of high mountains that stretch from Canada through the United States to Mexico.

The Rocky Mountains contain very high ranges separated by basins.

The Rocky Mountains contain long ranges of pointed peaks rising from forested basins.

What is the landscape like?
The Rocky Mountains is one of the largest mountain ranges in the world.

To the west, range after range of mountains take up the western half of the continent, finally disappearing into the Pacific Ocean in Alaska. To the east The Rockies face across the flat plains of North America like a huge impassable wall. This edge to the Rockies is called the Front Range. Its peaks are capped with snow through most of the year. This was the wall that the early explorers saw and that pioneers dreaded as they made their way westwards.

Behind the Front Range lie many further ranges of equally high and formidable mountains. Each range is quite broad and, although the mountains are high, they have not been formed into the knife-edged ridges of mountains like the Himalayas. At the same time, the ranges do not have the passes cut through them that have been made in the Alps. Much of the Rockies is still a wilderness, and large parts of it are still forested. It is also quite a dry place, especially in the basins between the ranges. Some of these basins are true deserts. The Rocky Mountain ranges are high and have few passes cut through them.

How did it come to be like this?
The Rockies used to lie on the western side of the North American continent. North America is part of a large slab of the earth's crust called a plate. It is one of a dozen large plates that slowly move over the earth's surface, dragged about by forces deep within the earth.

For the last 200 million years, the North American plate has slowly crept westwards. This has meant that is has pushed against the plate that forms the Pacific Ocean. Where the two plates met, the land became crumpled up to form high mountains. This is how the Rockies started.

The first mountains were all fold mountains. In time, they were worn away. As North America continued to creep west, new chains of mountains were formed (the Sierra Nevada and Coast Ranges of California and Cascades of Oregon and Washington), to the west of the Rockies, which left the Rockies closer to the middle of North America rather than on the western side of it.

The formation of the new mountains caused the worn down stumps of the old Rocky mountains to be jostled up. As the pressure on them built up, so they broke up into huge pieces, some of which then rose up to form the mountain ranges. The broken edges are called faults, and the edge of one of these faults is responsible for the sharp edge of the Front Range.

The Rockies do not have many volcanoes, but one exception is the area underlain by Yellowstone National Park. Here an ancient volcano still provides enough heat to power the world's largest system of geysers, including the famous Old Faithful, which jets water into the air about once every 50 minutes.

The weather
The Rockies cover a huge distance, and so the weather in the snow-clad northern Rockies is very different from the sun-drenched southern Rockies.

The Rockies may be snow-laden throughout the winter, but they also have a very high number of days with blue skies and sunshine.

What is the weather like month by month?
The Rocky Mountains are a mountain chain that stretches from the Arctic to the tropics. Naturally, the weather will be different in different parts of this vast area. However, all of the weather comes either from the west (in winter especially) or from the south east (in summer) and so the mountains all share some things in common.

The Rockies block the path of air blowing from the Pacific Ocean. As a result, the western ranges are wetter, and in winter snowier, than the eastern ranges. In between each range there is a rainshadow region in which the land is almost like a desert and the sky mainly clear.

In the summer, the centre of North America heats up under the effect of the sun. This draws air up from the Gulf of Mexico, and it flows north along the side of the Rockies, setting off torrential thunderstorms. In summer, the eastern ranges therefore get more rain than the western ranges.

The Rocky mountains are dry and cold in winter, with only occasional snow showers. This makes them ideal winter playgrounds, and many of the highest ranges are important ski resorts.

Seasons
The Rocky Mountains are sunny throughout the year. The changes in the seasons are marked by the rise and fall of the snow line.

Summers are very hot and winters very cold. But the dry air makes both summer and winter pleasant seasons. Towns in the high mountains can be isolated from the outside world for weeks after a heavy snowfall.

How does the weather change with the seasons?
The Rockies have a long period of cold; more than nine months of the year in the north, less than six in the south. All of the mountains get deep snow, but the basins may have had little more than a dusting because they lie in the rainshadow of the mountains. In the spring the snow quickly melts from the basins and then slowly rises and uncovers the pine forests. The extra rainfall in summer keeps the high mountains green, and attracts many people for vacations.

As the snow melts away, the mountain flowers come into bloom. 'Alpine'-type meadows are common (and much more extensive than in the European Alps).

By the summer, rain is in short supply and the west becomes dry and dusty. The eastern part of the Rockies experiences moist air from the Gulf of Mexico and as a result severe summer thunderstorms and flash floods are common.

In the fall/autumn, frost comes readily to the mountains. Then, as more westerly winds bring snow, the snowline begins to move slowly down the mountains so that, by November, snow is lying in most places, packing up to many metres thickness on the summits.

How does this affect wildlife?
The Rockies contain extensive wildlife. Many areas are still true wilderness. Large animals, such as the brown bear, hibernate or move down to lower altitudes. Bison also move to more sheltered places. Moose begin to browse on the trees if they cannot reach the ground vegetation through the snow.

Brown bears are common in the mountains during the summer. In winter some move down to lower elevations while others hibernate.

How does this affect farming?
The Rockies contain some ranches. It is not an intensively farmed region, because it is both dry and cold. Ranchers have to get their herds into the yards throughout the winter.

How does this affect transport?
The high passes are sometimes closed by snow in winter, but continual snow ploughing on the main roads keeps them open most of the time. All of the smaller passes are blocked from October to May. Keeping passes open is a high priority - but only for the main roads.

How does this affect tourism?
Tourism is one of the main activities of the Rockies. In winter, cross-country skiing, as well as skiing on piste is a widespread activity. Rocky Mountain snow is regarded as some of the best sports snow in the world. It is also reliable, and accessible. In summer, the fine sunny weather attracts many tourists. The Rocky Mountain National Park is just one of many recreational centres down the spine of the Rockies. The park road is the highest crossing of the Rockies at over 4000m.

How does this affect homes?
This area was settled relatively recently. The oldest homes are log cabins, dating from the 19th century. Most homes are modern and so do not have to be built in any special way.

Weather hazards
In the high Rocky Mountains, avalanches and blizzards are common in winter. Snow can pile up to many metres deep. In summer, there is a risk from flash floods in some narrow valleys. Huge snowdrifts are common in the mountains.

What is a hazard?
A hazard is a natural event that can cause injury, loss of life or widespread damage to property. The hazards vary with the seasons. In winter, the main hazard is from snowdrifts and blizzards, which can leave people stranded on roads in very cold conditions. On the steep mountain slopes avalanches are also a hazard.

In summer, torrential rainstorms often crash on to the slopes of the mountains. As rainwater runs over the steep slopes, it causes flash floods. These have killed many holidaymakers in the past.

How can people protect themselves from hazards?
This is a region with a small population. In general there is no need to build in hazard prone areas. The main people at risk are those who camp beside rivers in the flash-flood areas in summer. Summer flash floods are a real hazard during summer in the mountains.

Are people making hazards better or worse?
People have had relatively little impact on this area and have not changed the hazard risk, except for a slight increase in avalanche risk in the deforested skiing areas.

Homes and towns
The Rocky Mountains are sparsely settled. The small towns are mainly in the warmer basins between the mountains. A few mining towns were sited high in the mountains close to mines. Many of these are now ghost towns. Ghost towns can be found in the remote Rockies.

Where have people chosen to live?
Four kinds of people live in the Rockies:
those who live in towns and depend on people passing through the Rockies. They are concentrated in small towns where roads meet in the basins.
Those who live on ranches in the basins away from the main roads
Those who live in the skiing resorts
Those who lived in old mining towns that are now ghost towns or tourist centres.
In the past, towns were established to mine valuable minerals. Many of these were high up in the mountains. Some have been converted to tourist centres.

Some people have also retired and live in the warmer, more southerly, towns situated in the basins and foothills of the Rockies.

How have people traditionally lived in the area?
The native Americans lived in many parts of the Rocky Mountains. Those who lived in the north tended to migrate between upland settlements in the summer, and more sheltered settlements in the winter.

There was no permanent settlement until pioneers arrived in the nineteenth century.

What changes have there been in the last 50 years?
The area has changed a little, but not a lot. The mines have mainly closed. The roadside towns have grown a little, with a few more hotels. The ranching has declined slightly. The main changes have been to places where the retired people have come to live. Even so, the numbers living in this area are quite small.

What changes might there be in the future?
Water and other supplies are limited. These will put a cap on the number of people who can live in the southern Rockies. The ski resorts will probably increase, but the area is very large and so the mountain environment is not threatened in the same way as in mountains elsewhere.

Travelling about
The Rocky Mountains have few roads because there are few passes. Most roads run east - west and are designed to cross the mountains using passes. The roads that run north - south are mainly only local highways. Aircraft are used to travel between distant cities. Roads run straight across the basins, then have to find a more twisting route to get across the ranges.

How do people get to the Rocky Mountains?
The Rocky Mountains are one of the world's largest mountain chains and there are many ways to get to them. However, in general, people have to choose the side of the Rockies that they want to visit, because the high crests have very few passes across them.

If people are touring, they may want to visit the Rockies from a city like Salt Lake City in Utah (for the western side of the mountains) or start from Denver in Colorado for the eastern side. In both cases most people would fly in from their home city. From their destination airport they would rent a car.

Public transport is found only on some main routes and is rarely suited to getting about in the Rockies.

Some people might drive to the Rockies from their home if they are planning on a long vacation. This would especially be the case for people who own recreational vehicles (RVs, campervans).

How do people travel in this area?
This is a sparsely populated area. Most people have their own road transport. Railways are used to transport some goods, but they are not geared to serving passengers. People wishing to travel between major cities mainly use aircraft. Tourists mainly use their own cars, or they rent at airports.

How has the landscape affected travel?
The main problem is that the ranges run north-south and there are few gaps in the ranges. This has restricted travel by rail and road to a small number of routes. The distances are also huge. As a result, travel in the Rockies takes time.

How has the weather affected travel?
The main problem with transport is winter snow. Most major passes are kept open through the winter but all the small ones are closed.

Tourists
Tourists have a big impact on the area by providing many people with a living. However, the number of tourists is nowhere near as large as those visiting more easily reached mountains, like the Alps.

Rocky Mountain National Park near Denver Colorado is one of the most heavily visited parts of the Rocky Mountains. Yellowstone National Park on the Wyoming-Idaho border is even more popular.

What kind of tourism affects this area?
The main form of tourism affecting the whole area comes from those who are touring in their cars.

How does the weather affect tourism?
Both summers and winters have long periods of sunshine. The dry, sunny and yet snowy conditions make the area very suitable for winter sports. In the summer, the hot sunny conditions are made more pleasant by the altitude and breezes, so that, especially in the north, it is ideal for touring.

What seasons do people go?
The main touring season is from June to September. In the South it is longer by a month at each end. The main skiing season begins in November and goes through to February and March.

How has tourism helped local people?
It has provided many jobs in small towns that would otherwise have difficulty surviving. Certain winter sports areas employ large numbers of people seasonally.

How has tourism had a bad effect?
Tourism has not so far had a bad effect on this region. The most visited areas are mainly National Parks and National Forests, and these are controlled by the National Parks Service or the National Forest Service.

Environment
Much of the area is wilderness. Hunting and the fencing of land has had the most effect on reducing the numbers of wildlife. Moose are one of the many large mammals to roam the wilderness of the Rockies.

How have people altered their environment?
Although much of the Rocky Mountains seems untouched, the environment has changed in a number of ways:

In the north, large areas of forest have been logged
In many of the basins, the land has been fenced off and used for cattle grazing
The rivers have been dammed and the waters diverted
Mining has polluted some areas close to the mines
Tourists are eroding some of the more popular mountain areas.


How might this affect the natural world?
The wildlife is often disturbed in areas close to roads. Wildlife often cannot get through fences, and so they cannot migrate from one area of the Rockies to another. This may prevent some animals from getting enough food to eat.

The natural pattern of wildlife may be altered. For example, bears are attracted to camping grounds because of waste food left out. Bears then accidentally attack property and sometimes people, leading to demands to shoot the bears. This results in smaller bear populations.

Hunting has resulted in the loss of many wild animals. Although widespread extermination of animals mainly occurred in the 19th century, there is still pressure to kill wildlife because it competes with the grazing needs of farm animals.

How could people improve matters?
Simply by realising that this special area is still the home to precious animals, rather than thinking of it as an area to use up. The farming quality of the land is low and it could be left entirely wild.

It will help keep pressure down by continuing to make it difficult for tourists to wander about in the landscape at will.