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The Johnston Ridge Observatory will be closed for the winter season at the end of the day on Sunday, November 9. The observatory will reopen in mid-May 2009 for the 2009 visitor season (opening date will be dependent on weather and snow levels).
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Even before its recent loss of height, Mount St. Helens was not one of the highest peaks in the Cascade Range. Its summit altitude of 9,677 feet made it only the fifth highest peak in Washington. It stood out handsomely, however, from surrounding hills because it rose thousands of feet above them and had a perennial cover of ice and snow. The peak rose more than 5,000 feet above its base, where the lower flanks merge with adjacent ridges. The mountain is about 6 miles across at its base, which is at an altitude of about 4,400 feet on the northeastern side and about 4,000 feet elsewhere. At the pre-eruption timberline (upper limit of trees), the width of the cone was about 4 miles.