The latest installment of Accretionary Wedge is a call to write about the “most memorable/significant geologic event that you’ve directly experienced”. This will be my first contribution to Accretionary Wedge, so if I’m doing it wrong, someone please let me know!

When I first heard the topic, I thought “well, I grew up in Southern California, so I’ve experienced lots of geologic events.” I’ve experienced more earthquakes than I can remember.

The 1994 Northridge quake knocked me out of bed.

I felt the 1987 Whittier Narrows quake while walking to school.

Then there was the one (unnamed, as far as I know) that occurred while I was in the shower, and my 14 year old self panicked at the thought of having to run outside naked.

I was in San Francisco a few weeks after the 1989 Loma Prieta quake, so while I didn’t feel it personally, I saw the aftermath up close.

I was at Mt St Helens a few months after the 1980 eruption. Again, not a direct experience of the event itself, but that experience is certainly something I’ll never forget.

(The real question here is why I didn’t become seriously interested in geology until a couple years ago!)

I have no pictures of my own to go with any of those events, so, while memorable, none deserve a dedicated blog post.

But a few months ago I got to experience something that will stay with me for a long time, and I’ve got lots of pictures to go with it, and I’ve been neglecting this blog for far too long, so here goes.

In mid-September I went to Zion National Park. I drove down from Provo on a Wednesday. I was still a couple hours away when a thunderstorm started up, but it was mostly gone by the time I got to the park.

By the time I got set up in the campground, the day was absolutely gorgeous.

The next day, the weather remained beautiful, but the Virgin River was clearly carrying a heavy sediment load from the previous afternoon’s storm.

That afternoon, I went on a ranger-led hike, and heard about Zion’s ephemeral waterfalls. I was disappointed that I’d missed them.

By Friday morning, most of the sediment was gone.

I took that picture across the road from Zion Lodge, where I was going to attend a ranger talk. One hour later, this was the view across from the Lodge:

It’s hard to see exactly what’s going on there because of the rain between me and the rock. But you can see, there in the middle, one of those waterfalls I’d heard about. This wasn’t a little shower, this was a deluge, complete with hail.

A couple dozen of us were huddled under the bus shelter waiting it out. (During the tourist season, private vehicles are not allowed in the upper canyon. You have to take a shuttle bus to get to most places in the main canyon.)

Then we heard the news that there was a mudslide over the road down canyon from the Lodge, so we were stranded indefinitely. Most people went inside, but the thought of standing around with a bunch of soaked, grumpy people didn’t appeal to me. So I stayed outside and watched the waterfalls grow…

…and change colors…

…and create beautiful veils of streaming water.

It turns out that the mudslide wasn’t as bad as it sounded, and was cleared (at least enough to allow the shuttles to pass) within an hour. This is what it looked like when I finally got on a shuttle bus.

That’s supposed to be the road.

Compare the sediment load here (from the Visitors’ Center) to the one above near the Lodge. This picture was less than two hours later.

Things had settled down by that evening, and our ranger-led shuttle tour went on as planned. The ranger told us that the discharge had gone from 60 cfs to 800 cfs during the storm.

I don’t know if it’s possible to say how much of Zion left the park via the Virgin River that day, but I was glad that I was able to witness a small (teeny, tiny) part of the millions of years old process.