At long last, I have finished going through the entire USGS database of photos tagged Mount St. Helens. There were so many treasures! I'll be bringing them to you for some time.
This is a fabulous, almost sci-fi view of a bit of pumice under a scanning electron microscope. Those textures are just exquisite! You'll notice it's more air than substance, which is why pumice tends to float.
Even after the enormous May 18th eruption, Mount St. Helens had a lot of exploding left to do before she could settle down. This magnificent photo of her July 22 1980 eruption shows her hurling a thick column of ash at the sky, while a pyroclastic flow roars out through the gap in her northern crater wall.
The July 22nd 1980 eruption was quite thoroughly photographed. I'm hoping to put together a gif of some sort once I've located all the slides and put then in chronological order, but in the meantime, here's this really striking shot of the third eruptive pulse. She still had a lot left in her.
Here are some geologists poking round inside a pit on the pumice plain. This is a few years after the May 1980 eruption, so erosion has got well underway, but you can see how raw the landscape is still. And that is one huge pit. The caption doesn't say, but I believe it was caused by one of the steam explosions.
This may only be delicious to those of us who are really in to geology, but: erosion in lahar deposits. Yum! It's taken about a year for streams to cut down that far.
Note for creationists: once again, these are unconsolidated deposits. Don't get all excited by the pace of erosion here.
Here's a view across the North Fork Toutle River valley, looking into the maw of Mount St. Helens. The valley is filled with debris avalanche and blast deposits. Note the huge trees stripped of all their limbs and stuck into the deposits any-old-how.