Weather mix evokes reaction from Mount St. Helens

By Keri Brenner
The Olympian

The mix of cold, clear air in recent days after a period of rain resulted in a small plume of steam and gas last week at Mount St. Helens, said Carolyn Driedger of the Cascade Volcano Observatory.

Driedger said the plume was not high enough to create any hazards for planes or any cause for emergency alarms, but was a reminder that the volcano has been continually erupting lava since October 2004.

"Whenever we have clear skies, just after a period of moisture, we often can see a plume," Driedger said. "It's really interesting that this eruption is continuing; it's not the norm of other volcanoes around the world."

The plume was formed Thursday, the same day as a 1.5-magnitude earthquake. A plume is created when rocks fall off and expose patches of hot lava. The hot lava makes contact with the extremely cold air, causing a plume of mostly steam and some gasses.

"I saw it when I was coming into work," Driedger said.

The small earthquake was a routine occurrence and did not require notification of emergency agencies, Driedger said. The only time she would notify the state Emergency Management Division at Camp Murray would be if volcanic conditions change dramatically, she said. The state would then handle contact with surrounding counties.

Mount St. Helens exploded in 1980. Other than a few steam blasts after that, there was no activity until September 2004, when a swarm of earthquakes occurred. That appeared to have triggered the start in October 2004 of continuous nonexplosive lava eruptions.