Wildflower Wednesday: At Mount St Helens

Part of our USA road trip this summer included a visit to the Mount St Helens National Volcanic Monument. Here's a view of what remains of the volcano today. You can see the Toutle River valley is still full of volcanic ash, even though it's many years since the volcano finished its eruption.

NAH took this picture, so you can see how different things were in 1980 and the drama of the first few moments of the eruption the mountain is famed for. I'd recommend a visit to the 4 visitor centres there, especially the talks given by the park rangers. It's not often you get to mess around with plasticine to see how plate tectonics and the various types of faults work! Nor is it every day that you get to have lunch outside with a volcano ;)

I'd spotted on the map there's something called a Sediment Retention Structure built by the US Army Corps of Engineers. It turned out to be this dam-like structure built across part of the Toutle River.

When the volcano erupted its effects were felt for many miles. Yakima, the town we'd stayed at a few days previously had day turned to night by 9.30am owing to the ash debris falling like snow. The mighty Columbia River we'd sailed on the day before had its depth altered from 40 metres to 14 metres pretty much overnight by the amount of debris carried down rivers like the Toutle. The Army Corps were brought in to dredge the Columbia River back to its normal depth, but it soon became clear that this was too expensive for a long term solution.

So they built the Sediment Retention Structure. The 'dam' contains many pipes through which the river continues to flow. These are gradually getting clogged up by the volcanic debris still being carried down the mountain (it's a bit like a very slow motion avalanche). This is part of the design. The river's height will gradually build up behind the dam as the pipes get filled, until it finally spills over the dam in around 2030.

That's assuming there's not a further eruption of course. Apparently there's another cone building up in the volcanic crater :o

I asked the park ranger how many of the mountains in the Cascade range are volcanic. All of them came the reply. It's just that Mount St Helens is the most recent eruption and the most active seismically at the moment, the rest are simply sleeping giants. Mount Rainier is considered to potentially be the most dangerous. That's probably why I'd seen evacuation routes signposted at the side of the road when we were there.

So where do the wild flowers come into all of this? Well, to get to the Sediment Retention Structure there's a mile hike through the woods to get there. It's a very pleasant walk which NAH left me to tackle alone. At first I felt OK about this, but I must confess I was worrying a bit about what might happen if I came across a bear when I took this photo. It does give you an idea of what this part of the forest and understorey vegetation looks like though :)

Looking more closely at the understorey, I was delighted to find there were lots of Tiarella trifoliata or foam flower amongst the ferns. Having read in my Heuchera book about how many of the native forms of these and their Tiarella cousins prefer shady and mountainous habitats, it was great to see my book coming to life in front of my very eyes :D

Do visit Gail's Wildflower Wednesday to see what everyone else has discovered this month.


  1. How ever did you move away from looking at the view in the top photo? I expect NAH is grateful to volcanoes and bears for making it clear that standing still for ever might not be a good idea. Otherwise, you might never have gone home!

  2. Lucy - it was really hard to move away just as it had been difficult to move away from so many of the spots we went to on holiday.

    We nearly didn't go to Mount St Helens: it was on my must see list but I'd drawn up a much shorter itinerary to cut down on the number of miles we drove. I'm so glad that D NAH's friend from uni days persuaded him a longer trip would be so much better. It was.

    NAH was fascinated by the whole Mount St Helens experience (hence the photo he took). It's amazing to think that the 1980 eruption is small beer as far as cataclysmic volcanic eruptions go.

    When we drove to Yakina from Mount Rainier I suddenly realised we were driving through miles of layers of old lava flow hundreds of metres thick. I have a post lined up to tell you all about this another time.

  3. That should read Yakima. not Yakina!

  4. PS having lunch outside gave us a couple of hours to continue gazing at the view - hence my calling it lunch with a volcano ;)

  5. PPS NAH's uni friend had a bear visisting her garden at night whilst we were there, hence my awareness of how dangerous they can be. The problem is, what you do when meeting a grizzly bear is different to what you do for a brown bear and I couldn't remember which was which! Then I heard some chilling crashing in the undergrowth...

    ... luckily it was caused by a family of 4 intent on visiting the same spot as me.

  6. A much more serious dilemma than remembering what to do when stung by a wasp or bee . . . !

    . . . but was it a family of four bears or four humans?

    P.S. WV is 'hotagnit' - isn't that a great word? It ought to mean something!

  7. 4 humans thank goodness, though they did disturb the peace and quiet a bit ;)

    That's a very good word - perhaps it's the trouble I would have been in if it'd turned out to be a family of 4 bears?

  8. coastal cities, such as seattle, also have evacuation routes due to tsunami risk associated with being on a volcanic 'ring'. yellowstone national park sits on another rather large (inactive) volcano...the yellowstone caldera. although, i admit, the site i would most like to see isn't all that 'touristy'..it's the new madrid quake site. given the destruction of mt. st. helens, it still amazes me how quickly wildlife has recovered.

  9. Petoskystone - ahhh the Pacific 'ring of fire' I remember from schooldays :)

    Isn't the Yellowstone area beginning to bulge - leading to speculation that it's waking up? I seem to recall reading that somewhere...

    Must look up the madrid quake to see what that's all about.

    Yes there was lots to see in 1 of the visitor centres about how nature has come back so quickly, but my first picture of this post also made us realise nature still has quite a job left to do. When you see the riverbed looking as awesome and grey as that, it helps you to realise just how destructive things must have been.

  10. We had volcanic ash from the eruption in Montreal - about 3500 miles away. A thin film covered everything. Very weird that something on the other side of the continent could find its way to us. Lovely little foam flower on the trail - an excellent wildflower.

  11. Gosh Barbara - I didn't realise it had travelled that far! Thanks for telling us about it.

  12. Interesting and beautiful post - it's hard to think of Tiarella's as being wild flowers - but they look just right in that setting.

  13. Thanks Elaine - they looked just right en masse. A case of right plant, right place :)

  14. Oh my..I have not thought of the eruption in so long. We were living on Salt Spring Island and I remember coming outside in the morning, a day or so later and everything covered in the ash..the car,everything..the air was yellow, the sky bluegreen... Such a sad memory. But your journey brightened my heart, knowing Tiarella's grow there now and the changes that have been made. Thank you for sharing this!

  15. What an amazing place to visit. I seem to remember the eruption affected the weather here in the UK too, but checking on the internet, it seems the eruption of El Chichon in Mexico two years later had a much worse effect. Yet it's Mount St Helens we remember - possibly because it was such a dramatic eruption.

  16. VP, We got married in 1980 and headed west to visit family~We could see the ash cloud moving across Kansas and Missouri~very strange. Love that you are sharing in the WW and showing us native plants from the US! xxoogail

  17. gardeningbren - each of the 4 visitor centres tells a different story about the eruption. One of them is about the personal stories about the eruption. Thanks for telling your story here.

    Victoria - I wrote about the impact volcanoes have on the weather in my ABC of Weather

    Gail - I have a sense of irony! I'll run out of stories soon and will have to start on the UK :)

  18. Mark - writing up these pieces about our holiday has made me appreciate what we did even more :)


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