The Situation
Here's something not many of us get to see, unless you live near Mount St. Helens and get out of bed at sunrise.
St. Helens continues to spew ash while its forming a lava dome in the crater and keeping us on our toes with minor tremors (which are really exciting when hiking there!) Here, in these sunrise shots, she appears to be blowing smoke rings. Anything so benign is welcomed given recent history.
The smoke rings are formed by cooler air flowing over the crater being pushed up into the atmosphere by warm air from the crater, as it goes up and over the top. The moisture content and initial temperature are just right to cause the moisture to condense from a vapor state to small water particles at the higher altitude. Then, when the now heavier air moves past the peak on it's downward path, the particles evaporate back to an invisible vapor. Absolutely clear, right?
The two "pancakes" you see describe two layers of air, both the warmer and the heavier, thus making these awesome pictures possible.
Credit Where Credit Is Do
I did not take these pictures; however, the person who did remains unknown. A local friend sent them to me by e-mail. They are just too spectacular to keep a secret!
2 comments:
Great photos! I remember the big eruption back in 1980, and how my dad's truck came back covered in an inch of soot. (He went up there for a big motorcycle race not too long after.)
Thanks. I wish I could take pictures this well. Of course, getting up every morning at 5:00AM to see if conditions are right is not my idea of a good time.
BTW, I happened to be moving from Seattle to Portland when it blew. Postponed my trip for 48 hours until I-5 reopened. Because of the dust, the speed limit was 5 MPH with semi's leading each caravan behind a Highway Patrol car - so the speed was REALLY 5 MPH. Took almost 7 hours to make what would have normally been 2.5 hours. Wearing a face mask and hoping like crazy that the dust wouldn't clog up the air cleaner. Those of us with fuel injection seemed to do better than the carb jobs, although it took a year to remove all of the dust from my car. Oh ya!
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