Katmai 's 4 million acres are home to more than 2,100 brown bears . Always maintain a 50-yard distance from bears and never separate a mother from her cub . The bear population in Alaska is estimated at about 10,000 - 12,000 bears. The eruption created the Valley of Ten Thousand Smokes , 40 square miles of volcanic ash .
Katmai 's 4 million acres are home to more than 2,100 brown bears . Always maintain a 50-yard distance from bears and never separate a mother from her cub . The 1912 Novarupta volcano eruption was the largest of the 20th century . The eruption created the Valley of Ten Thousand Smokes , 40 square miles of volcanic ash .