What is the largest alpine lake in North America?
Lake Tahoe on the California-Nevada border has a 105,000-acre surface, holds 39 trillion gallons of water, and is almost 1,600 feet (488 meters) deep. Fate? 96. Have there always been continents? Not as we know them today. Many scientists figure Earth began as one huge continent — dry as a bone. Water was delivered in comets, the thinking goes, and the oceans developed. Much more recently, all the world’s landmasses were huddled into one supercontinent called Pangaea. It began to break up about 225 million years ago, eventually fragmenting into the continents as we know them today. 97. How much volcanic ash can fall in a day? I can only give an example. During the 9-hour period of most vigorous activity on May 18, 1980, Mount St. Helens dumped more than 540 million tons of ash over an area of more than 22,000 square miles (56,980 square kilometers). It was the most destructive volcanic eruption known to occur in the United States. Fifty-seven people were killed by the eruption includi
