Mt. Mazama Ash Mystery

I recently went to visit my daughter, Jennifer, in Medford Oregon. I arrived at the La Quinta Motel and went to my room on the 4th floor. It had been a long drive and I was tired. I walked over to the window and pulled the curtains open and there in front of me was Mt. Mazama.
Mt. Mazama is breathtaking and dominates the skyline looking east from Medford. It is hard to believe that it once was nearly double the size it is now. Most people come to Mt. Mazama to see Crater Lake which lies within it. 7000 years ago, Mt. Mazama exploded with a force several hundred times that of the Mt St. Helens eruption in 1980. After the eruption of Mt. Mazama, the throat of the Volcano was empty of it's magma and ash, and over thousands of years the rain filled it creating a natural master piece. I have been up there and stood on the rim and looked down into the stunning blue water. I have heard that it is too deep to be measured accurately.
It was by pure coincidence that the day before leaving for Medford, I happened upon an article indicating that in the upper Skagit River Valley is a deposit of Mt. Mazama ash 30 meters thick. It is sitting there in one big lump on both sides of the Skagit River and was discovered when Hwy 20 was cut through. Now keep in mind that Skagit County is near where I live in Bellingham, 400 miles away. How did the ash get all the way there and how did so much of it end up in the same place 10 meters thick? It is deposited across a narrow part of the valley as if a Giant had taken a giant scoop of the ash from down in Oregon, carried it all the way to Skagit County and dumped it out in that particular place. I just could not wrap my mind around this and was determined to visit the site when I got back to Washington to see it for myself.
I enjoyed my visit with Jennifer and my grandchildren. My other daughter Melissa and grandson Ethan had come with me and it was a nice trip and the weather was warm. The time went fast and before I knew it, it was time to head north for home. But during the time spent there I found myself staring at Mt Mazama as it seemed to be visible from everywhere we went. I took numerous pictures but didn't seem able to take one that did the Volcano justice. This was May and half the mountain was still white with winter snow. I felt deprived when looking at it because for thousands and thousands of years Mt. Mazama had been twice the size it is today and that there was no way for me see it the way it was then. Generations of humans did see it though, and I am envious. There were people living here when it erupted and I feel sorry for them. I imagine it killed some of them directly and reeked havoc in the lives of those who survived. That part of the world was different after the eruption and it took hundreds of years for the earth to recover.
My mind was on that ash deposit the whole way back to Bellingham. I eagerly began reading everything I could find about the eruption of Mount Mazama. I learned that the eruption had occurred 7000 years ago and that ash was deposited about 2 inches thick on the ground as far as 200 miles into Canada and actually covered most of the Northwest. So, again I wondered how did it end up 10 meters deep in one spot? I also learned that this layer of ash 7000 years old serves as a marker for archeology excavations. The layer is clearly evident and so right away Archeologists can determine if an artifact is more than 7000 years old by where it is in the ground in relationship to the layer of Mt. Mazama ash.
I have always been fascinated by the geology of the Earth and thought I would like to major in it in college. But realized that I was just not a math, chemistry, physics kind of guy. But I do love rocks and volcanoes and earthquakes and the rest. I can spend hours looking around in the desert or in the mountains at these things trying to experience their history on as many levels as possible. I was tempted to assume things about how this ash got here all in the same place, but still, in the back of my mind I knew there was a reason for this and that I had no idea what that could be.
I had to get to the site as soon as I could. One Sunday morning shortly after returning from Oregon, Marlene and I got up early, packed a lunch and took off in search of the ash. I had a description of where to find it from a geology field trip web site. It was a beautiful trip up Hwy 20 past Marblemount and on toward Newhalem. The site is between the two. I thought I had found the site and we got out of the truck and looked at what we thought must be the ash, but I could not convince myself that it was the ash. It looked like ordinary dirt and rock. But I thought that it might be ash and what else could I do. We continued up river and enjoyed the scenery and hiked a trail to an overlook that provided us with a breathtaking view as we took in the beauty of the river below and read plaques about the amazing history of man's ability to control this wilderness for hydro electric energy. I will write another blog about that another time.
When we got home, I reviewed my materials and found that I had miscalculated the location of the ash site, we had gone 7 tenths of a mile too far. The place I was looking at was actually dirt and rock. I was angry at myself for letting my excitement carry me away to the point of miscalculating the location. I told Marlene that I had made a mistake. She said that that was too bad but it would not be reasonable to spend more time and more money for gas to go back up there right away. And she was right it was more than 100 miles each way. But it was eating away at me. All night I was thinking about 10 meters of Mt. Mazama ash sitting up there waiting for me to check it out. In the morning, Marlene left for work at 5:30 am, I was on the road by 5:53 am. On my way out the door I grabbed Marlene's ice cream scooper and a sandwich baggie to collect samples. Being on the road erased my frustration from the day before. I was going to get this done and by the end of the day I would have in my possession actual Mt. Mazama ash.
Another reason I was so happy was that I had learned how the ash had ended up there 10 meters thick in that one place and it is an amazing story. I found the information in a on a geologic web site. It seems that John Riedel, a geologist with North Cascades National Park, put the mystery to rest in a report he filed several years ago. This is what happened, several hundred years before Mt. Mazama erupted, there was a massive rock slide in Skagit Valley. Rocks as big as small cars split from the steep mountain on the North side of the valley. The slide filled the valley with rock 130 feet high all the way across the valley effectively damming the Skagit River. This event created a lake 100 feet deep which backed up into the valley for 8 miles. Riedel named this lake lake Ksnea. The lake existed here for several hundred years and I am sure that generations of local natives hunted and fished along its shores and probably swam in its waters. It must have been beautiful. Then one day 7000 years ago Mt. Mazama exploded with unimaginable force. I wonder if the local Indians heard the blast that set the ash spewing into the sky. Or did they just begin to notice the fine talcum powder like textured ash falling silently from the sky. It fell for days and dimmed the sunlight. Riedel figured out that it had snowed in Skagit valley around the time of the eruption and the ash settled about 2 inches thick on top of the layer of snow throughout lake Ksnea's watershed area. Then, perhaps because of the ash, there was a rapid melting of the snow and the ash was washed into the lake at a relatively uniform rate. the ash was much lighter than soil so floated in the lake and because the river still had an outlet where it had been dammed, there was a current that carried it to a point about a half mile east of the slide where it slowly settled to the bottom of the lake, all at the same place, forming a 10 meter thick layer of sediment. Eventually, the river broke through the rock dam and emptied down the valley. The river eroded through the middle of the ash deposit but left it undisturbed on both sides of the valley where vegetation eventually covered it.
I easily found the ash this time and was amazed at how fine it is in texture. It is like powder. I took some pictures of it and collected a baggie full of it with the ice cream scooper. I have the baggie filled with ash on my bookshelf in my study. Sometimes I just hold it and sometimes I poke my finger into it and think about the journey it took from Medford to here. It is a reminder that our home, the Earth, is alive and dynamic. I would highly recommend that you explore it and appreciate when you can.