Steamy Mount St. Helens
On Sunday we witnessed a pretty amazing sight...a condensation plume rising above Mount St. Helens. This does happen fairly often, but typically the sight of steam rising above the volcano is obscured by our Northwest clouds and rain.
The biggest thing today's sight did for me was remind me that Mount St. Helens is an active volcano. The lava dome within the crater is steadily growing, and rising, and with time the growth of the lava dome could actually fill the 1980 crater...and become high enough to become a new conical summit.
This would be similar to what happened with the Bezymianny volcano in Russia. It had a large eruption, much like Mount St. Helens', back in 1956. By 1977 it's growing lava dome grew large enough so that it had become a new summit. You can see this new conical summit in the photo below (courtesy the United States Geological Survey).
Only time will tell just how active Mount St. Helens will be...and what it will bring to the Northwest.
Comments
How long until Mt. St. Helens will fill the 1980 crater?
Posted by: Michael | April 30, 2007 9:09 PM
Good question! I just spoke with scientists at the United States Geological Survey, and they provided an estimate of 178 years. So in 2185 the moutain's cone would be back! But keep in mind that that estimate is based on the current lava flow of around a cubic meter every two seconds...basically the cargo volume of a pickup truck every two seconds. As this lava flow fluctuates so will that estimate of 178 years.
Posted by: Joe Michaels | May 4, 2007 12:01 PM
Why do people talk so much about seeing steam rising from the volcano when that is impossible because steam is an invisible gas?
Posted by: Patrick O'Rourke | May 27, 2007 2:10 AM
Hi Patrick,
Excellent point...steam isn't necessarily the correct scientific term for what we are seeing rise from the mountain. Steam does develop, though. And as the invisible steam rises above the mountain, it cools. The laws of physics dictate that, as moist air cools, the water vapor within the moist air condenses - and a cloud forms.
So, what people see when they say they see 'steam' rising from the mountain is actually a condensation plume...or a cloud...forming as steam cools, and the moisture condenses.
Posted by: Joe Michaels | May 27, 2007 7:24 PM