Looking into the crater, August '06. You can see the steam as well as dust from rock avalanches. Deep inside you can also see the glacier.
Mount Saint Helens is an active stratovolcano in Skamania County, Washington, in the Pacific Northwest region of the United States. It is located 96 miles (154 km) south of the city of Seattle and 53 miles (85 km) northeast of Portland, Oregon. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century. The mountain is located in the Cascade Range and is part the Cascade Volcanic Belt, a segment of the Pacific Ring of Fire that includes over 160 active volcanoes. This volcano is well known for its ash explosions and pyroclastic flows.
Mount St. Helens is most famous for its catastrophic eruption on May 18, 1980. The 1980 eruption of Mount St. Helens was the deadliest and most economically destructive volcanic event in the history of the United States. Fifty-seven people were killed; and 250 homes, 47 bridges, 15 miles (24 km) of railways and 185 miles (300 km) of highway were destroyed. The eruption caused a massive debris avalanche, reducing the elevation of the mountain's summit from 9,677 ft (2,950 m) to 8,365 ft (2,550 m), and replacing it with a mile-wide (1.5 km-wide) horseshoe-shaped crater. The debris avalanche was up to 0.7 cubic miles (2.3 km³) in volume, making it the largest in recorded history. However, the scale of the blast is considered minor when compared with past debris avalanches elsewhere on Earth.
As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits. The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted. The largest of the dacite domes formed the previous summit; and off of its northern flank sat the smaller Goat Rocks dome. Both were destroyed in the 1980 eruption.