What is the difference between snow and hail?
Snow is water vapor that freezes in clouds before falling to the Earth. Hail is water droplets (raindrops) that have turned to ice inside of clouds.
How is hail formed?
Hail is ice that is formed in large thunderstorm clouds. Hail begins as droplets of water, normally destined to become raindrops, that are blown upward and subsequently freeze. They then fall lower within the cloud, where they collect more water, are blown upward again, and refreeze. The hailstone grows larger as it collects more and more ice and eventually falls to the ground.
How big was the largest hailstone?
In 2010, a hailstone that fell near Vivian, South Dakota, measured 8 inches (20.32 cm) in diameter with a circumference of 18.62 inches (47.3 cm), even after six hours of thawing. It weighed 1 pound, 15 ounces (878.84 grams). In 2003, a hailstone was recovered near Aurora, Nebraska, with a diameter of 18.75 inches (47.63 centimeters). The previous record was in 1970, when people recovered a hailstone with a 17.5 inches (44.45 centimeters) diameter in Kansas.
What is a glacier?
A glacier is a mass of ice that stays frozen throughout the year and flows downhill. Glaciers are capable of carving rock with their weight and slow, steady movement. They are responsible for the stunning landscape of Yosemite National Park in California. Large glaciers that cover the land are also known as ice sheets.
Are there still glaciers in the United States?
Yes, small glaciers exist throughout Alaska, within the Cascade Range of Washington State, sporadically across the Rocky Mountains, and also in the Sierra Nevada Mountains of California.
How old are glaciers?
Glaciers present today were created during the last stage of glaciation, the Pleistocene epoch, which lasted from 1.6 million years ago to about 10,000 years ago.
Glaciers around the world, including Serrano Glacier in O’Higgins National Park, Chile, have been receding due to global warming.
Did glaciers create the Great Lakes?
Yes, the Great Lakes are the world’s largest lakes formed by glaciers. During the Pleistocene epoch, glaciers inched over the Great Lakes area, moving weak rock out of their way and leaving behind huge, carved basins. As the glaciers began to melt, the basins filled with water and created the Great Lakes.
Are glaciers only found in cold, northern places?
No, glaciers are found in all six continents.
What is a tropical glacier?
Tropical glaciers are those found high in the mountains of tropical regions in the world. The Andes Mountains in South America contain 70% of the world’s tropical glaciers.
Is global warming causing the world’s glaciers to melt?
Many scientists believe that greenhouse gases from human activities, and the effect of this on global temperatures, are directly causing glaciers in all parts of the world to melt and recede at an unprecedented rate. It is thought that by 2030, there will be no glaciers in Glacier National Park in Montana. In East Africa, Mt. Kenya’s Lewis Glacier in Kenya has lost 40% of its size in just the last twenty-five years.
What are the consequences when glaciers melt?
Glaciers that have melted in the Himalayas, home to the world’s largest mountains, have filled up and burst the banks of nearby glacial lakes, filling rivers and causing widespread flooding and death to nearby populations downstream. Similar consequences will likely befall those now living near other glaciers around the world.
From where does the word “fjord” originate?
The word fjord comes from the Norse language and means “where you travel across.” It is significant to early Norwegians as a place to travel across to get to the sea when there were no bridges available.
What is a fjord?
During the ice ages, glaciers, which were prevalent at higher latitudes and elevations, became so large that gravity drove them to lower elevations, eventually all the way to the sea. On their way, glaciers would carve deep canyons in the surface of the Earth. At the end of the ice age, as the ice melted and the ocean level rose, these glacial troughs filled with seawater. These very dramatic-looking canyons with high cliffs hanging over a thin bay of water are known as fjords. Fjords are very common in Norway and Alaska.
What is the highest fjord in Norway?
The highest fjord is Sognefjord, which begins at a depth of 4,291 feet (1,308 meters) in the ocean and rises to more than 3,280 feet (1,000 meters).
Are all fjords found in Norway?
No. In fact, fjords are found throughout the world, wherever glaciers retreated and have cut into the earth, filling in and creating a huge valley of seawater. Notable fjords are found in Alaska and on New Zealand’s South Island.
Where is the longest fjord?
The longest fjord is in Greenland, at Scoresby Sund. It stretches more than 217 miles (350 km). English explorer William Scoresby mapped the fjord in 1822.
What is a dam?
By blocking the flow of a river, a dam allows a reservoir of water to build up. Dams are built in order to minimize floods, to provide water for agriculture, and to provide water for recreational uses. Dams in the United States are somewhat controversial, as the U.S. Bureau of Reclamation (established in 1902) and the Army’s Corps of Engineers battle to build more dams and control more water in the western United States. Many outdoor enthusiasts and environmentalists feel that dams are not always necessary.
What is the tallest dam in the world?
China is home to three of the top four highest dams in the world. The highest in the world, the Jinping-I Dam on the Yalong River in Sichuan Province in China, is 1,001 feet (305 meters) high. Tajikistan is home to the second-highest dam in the world, the Nurek, which stands 980 feet (380 meters) high. The United States’ tallest dam, Oroville Dam (in Northern California), is currently ranked twenty-fourth on the world list at 750 feet (228.6 meters) high.
How do farmers water their crops?
The process of artificially watering crops is called irrigation. In some areas of the world, agriculture can rely on rainfall for all of its water needs. In drier areas, usually those receiving less than 20 inches (51 centimeters) of rainfall per year, irrigation is required. Water is pumped from aquifers or delivered via an aqueduct to the fields, where it flows through small channels between plants or is sprayed through sprinklers. In very water-conservative regions such as Israel, water is scientifically dripped onto plants, thereby providing the exact amount of water necessary.
Although they were constructed many centuries ago, Roman aqueducts such as Pont del Diable in Tarragona, Spain, still stand today, a legacy of amazing engineering from ancient times.
How did the ancient Romans and Mesopotamians get water to their cities?
The ancient Romans and Mesopotamians built aqueducts to transport water between a source and areas where it was needed for agriculture or civilization. The Roman system was very extensive and was constructed