Notes from the Monsoon in Grand Canyon National Park

One of the most awesome things I've ever seen

Timing is everything. If one schedules a trip to the American Southwest in July or August, one may very well have to contend with the monsoons, the change in prevailing winds that brings warm humid air out of the Gulf of Mexico. The hot weather produces convection cells and intense thunderstorm activity, and flash flooding is a deadly possibility. Such flooding was in the news today in Utah and Arizona (here and here).

No, I didn't get a lucky shot, it's a screen capture from a video I took of the storm.

I got incredibly lucky in my travels this last week. We spent three nights on the North Rim of Grand Canyon (two of them in tents), and we got two evenings of dramatic clouds with all kinds of lightning and thunder in the distance. A bit of rain fell (with some serious thunder), but not enough to soak our gear. We had a delightful pair of evenings watching the light show from the viewing deck of the Bright Angel Lodge.

Storm cell over the South Rim of Grand Canyon

The third evening seemed calmer, and we saw only a few lightning bolts in the far distance. We headed into the lodge for dinner after the sun set and were enjoying our food, but we became aware that things were changing dramatically outside. The lightning strikes were happening only seconds apart, and the thunder was deafening. Rain was filling the canyon below. Like idiots we went outside in the raging storm to watch! I live in an area that gets maybe one or two thunderstorms a year, so I'm easily impressed. But there is another aspect: rainbows, sunsets, and lightning strikes are beautiful in their own right, but placed against the backdrop of one of America's greatest national parks they become truly awesome.

Sometimes you just need to look up

Though lightning was striking only a few hundred yards away, no one was hurt so far as I know. The rain fell for most of the night on Monday, and in the morning the ground was thoroughly soaked and everything felt fresh. The storms gained in intensity the following day, and there are now reports of flooding in places where I was eating lunch in the hot sun just a day ago.

One can never underestimate the power of flash flooding. It has proven deadly many times over through the years. No matter how strong you are, you simply cannot swim out of a rapidly swirling mix of mud, boulders, and water. If you are ever in the southwest exploring slot canyons, be aware of the weather. They became slot canyons precisely because of flash flooding. Even just driving your evening commute in Phoenix or Las Vegas can be dangerous. Take the warnings seriously.

The monsoons are dangerous, but they also bring needed rain to an area ravaged by drought for most of the last two decades. And they bring great beauty. I hope you enjoy this selection of photographs from my trip to the Grand Canyuon.

Into the Great Unknown: "Disaster" in National Canyon and the Volcanoes of Grand Canyon

Yeah, I was not feeling all that comfortable. It was day 13 on our journey into the Great Unknown, the Colorado River through the Grand Canyon. Day 13, and Lava Falls Rapid, the worst rated rapid on the river was...13 miles downstream. And I didn't know it yet, but we would arrive there at 13:00 hours. I'm not at all superstitious, but it was nice when the message written in the sands of time on the river shore appeared. Okay, I put it there myself, but I was apprehensive just the same!

We were camped at the mouth of National Canyon, which for many years was one of the larger and more popular campsites on the river. And then in the summer of 2012 it was hit by an apocalyptic flash flood that just about wiped the camp out of existence.

It's hard to imagine the scale of the flood. Estimates put the flow at 15,000 cubic feet per second. To put that into perspective, the flow of the entire Colorado River for most of our journey was around 8,000 to 12,000 cfs. And the flood was witnessed. A Western Rivers Expedition boat was passing by, and captured the flood entering the Colorado. Check out the video below by Joe Clark, one of the river guides:

Our campsite was rocky, but we found places to sleep. The rocky plain was barren of plant life. There is hope that a few artificial floods may ultimately deposit more sand on top of the bouldery deposits, but I wonder if the Bureau of Reclamation will be doing any artificial floods in light of the ongoing drought.

In any case, the experienced members of our crew were curious about how much the canyon above the river had been changed by the flooding. To me, the canyon was a beautiful place, regardless of how it might have once looked. How could I know any difference?

I could see that eroded ledges of Muav Limestone had indeed been buried in debris, and barely a single plant was visible along the course of the creek, despite the presence of a clear babbling stream. The going was tough in a few places. Boulders choked the channel.

The barren nature of the canyon was almost disturbing. It felt like there should be plants growing along the water. It drove home the point that no matter what ever else may happen, the rocks remain. Battered, broken, or polished smooth, they will last as everything else passes. But the rocks were also very beautiful, though, and the narrows spectacular. It occurred to me that this canyon, were it to be anywhere else in the country would be a national park or monument in its own right. Here, it was simply a tributary to the larger river, one of many.

The sun was high, and it was getting hot. We got onto the river and rowed downstream. We had reached a fairly long stretch with no major rapids, and lots of quiet passages through vertical canyon walls of Paleozoic sediments. In places we could see all the way to the canyon rim four or five thousand feet above us. The rim, and the world beyond, seemed remote and very far away.

I did a double take at Mile 176. Thousands of years ago massive landslide had broken away from the Supai cliffs out of sight above, and had come thundering over the Redwall Limestone, coming to rest near the river. It is called the Red Slide.

Over time erosion began to tear away at the debris-covered slopes, but here and there a large boulder protected the underlying soft material. The boulders were left standing on spires called hoodoos. It was yet another strange sight along the river.

I was on the lookout, because for the first time we would be seeing a new rock unit (the last "new" rock unit had been 100 miles upstream). It is not a familiar rock to the vast majority of visitors to the Grand Canyon, and in fact, most people are surprised to find out that such rocks are present in the national park: there are volcanoes and lava flows!

I looked high on the walls, and there was the first one, a fragment of black basalt clinging to the cliff. It was an exciting moment for me, because I've never seen these rocks before. I will deal with the profound effects of the lava flows in one of the next posts.

There were more signs of volcanism along the river where a sill had intruded into the Muav Limestone. It was one of the finer examples I've ever been able to photograph.
Soon we could see the source of some of the lava flows, a cinder cone on the high canyon rim called Vulcan's Throne.

We could also see the long tongue of lava from Vulcan's Throne that had reached the river. John Wesley Powell's description remains one of his most poetic writings:

Just over the fall a cinder cone, or extinct volcano, stands on the very brink of the canyon. What a conflict of water and fire there must have been here! Just imagine a river of molten rock running down into a river of melted snow. What seething and boiling of the waters; what clouds of steam rolled into the heavens!

And then, one of the strangest sights of all. A huge mass of congealed lava stuck right in the middle of the river. It was a plug of lava that filled the vent of one of the cinder cones. Called Vulcan's Anvil, it seemed like a message or a warning to river travelers, which indeed it is.

When we passed the anvil, we know we had less than a mile to one of the biggest challenges on the river: Lava Falls Rapid. The moment of truth had arrived...

The Anvil receded into the distance, and we prepared to scout the wildest rapid on a wild river.

Into the Great Unknown: We Interrupt This Scenery For a Very Recent Flash Flood and a Biological Disaster

After our fourth day on the Colorado River, we pulled into camp at Little Nankoweap Creek. The camp was in a beautiful location (as nearly all of our camps were), but as I selected a campsite, my attention was captured by an oddity. There was a huge splash of reddish brown mud laid across the sandy campsite like the edge of a lava flow. What was going on?

I realized I was looking at some of the very real results of the monsoon storms of the last five days. While Page was getting pounded and nearby Antelope Canyon getting flooded (events we didn't hear about until much later), numerous tributary canyons to the Colorado River were also being flooded. We were the first to see what happened at Little Nankoweap, as there were no footprints anywhere on the new flood deposits. It was no disaster in the big picture of things, but it was a marvelous small scale example of how the Grand Canyon got grand.

Flash floods and debris flows are the tools that erosion uses to deepen tributary canyons and widen the big canyon as a whole. Rock falls and avalanches choke the bottoms of gulches, and every decade or two a cloudburst sends torrents of water down the creeks, forming a slurry mix of mud and rock capable of transporting gigantic boulders. These masses of boulders get dumped in the Colorado and end up blocking parts of the channel, forming the characteristic pools and rapids. The spring floods that once surged through the big canyon would ferry the boulders downstream or grind them into sand and silt, and in this way, the Grand Canyon took shape.

 I had to take a closer look, knowing that the small mud deposit in camp was simply an overflow from the main channel. At the height of the storm, the mud was flowing over a wide area. The main channel (below) was being scoured, and rocky debris was flowing into the Colorado.

In the aftermath, a small rocky delta had formed, and the course of the river slightly changed. This particular event would soon be erased by the normal flow of the Colorado, as it was composed mostly of easily moved pebbles. I imagined the same event magnified several times, as in a once-in-a-century storm, and could see in my mind gigantic boulders changing the river on a larger scale. One of these events happened in 1966 at Crystal Rapids, turning a former riffle into the most terrifying rapid on the river (aside from Lava Falls).

We explored the channel for some distance, and found the Nankoweap Trail where it crossed the streambed. It wasn't there anymore.

The rocky steps the trail utilized to climb out of the channel had been removed by the flood (the trail is a bit left of center in the picture below).

We headed back to camp for a delicious meal of fish tacos, and hit the sack.

In the morning, I was covered with bugs. Or more properly, bug larvae. There were hundreds of them on my tarp. They were crawling all over the tamarisk tree I had camped under, and wriggling in the sand at my feet. I asked what they were, and our trip botanist pointed out that they were tamarisk beetles, and I immediately understood what was going on.

Tamarisk trees (also called salt cedar) are found all over the American southwest along river courses, but they aren't a native species. They come out of Eurasia, and having no natural enemies in their American environments, they have proliferated to the detriment of practically all competing species. They concentrate salt on their leaves which ends up in the soil, preventing the growth of other plants. They tend to form impenetrable thickets on river floodplains. They don't offer much in the way of food or shelter to most native species, and with deep taproots, they tend to transpirate vast amounts of precious groundwater into the atmosphere (some estimates put the water loss at 2 to 4.5 million acre feet per year across the southwest, enough to meet the needs of 20 million people, or to irrigate 1,000,000 acres). Some desert rivers stopped flowing on the surface after being invaded by the tree.

What's worse is that they are hard to kill. Cut them down and the taproot sprouts vigorously. Apply herbicides and many times they will sprout again anyway. A single plant might produce 500,000 seeds a year, and they can travel down the river, sprouting as they come to rest in wet sand.

I had noticed when we left Lee's Ferry that some of the tamarisks were looking a bit yellow (below), but didn't give much thought to it. It turns out that the Tamarisk Beetle loves tamarisk leaves and nothing else. After years of testing, the (also non-native) beetles were released into the wild, and they began an effective campaign of slowing the growth and spread of the tamarisk in the wild. And unlike some other such experiments, the bugs didn't start eating other native species. It is a reasonable hope that the bugs might one day lead to control (but probably never eradication) of the tree.

The trees actually provide some welcome shade in many of the river camps, but so would willows, cottonwoods, and mesquite trees if they weren't getting crowded out.

On the way back to camp, I spied an orange-breasted bird in the catsclaw acacia. I snapped a picture, and thought it might be a nice way to end a post that might seem a little depressing. But then...

 ...a rather majestic buck wandered through the edge of camp. So I will end with him instead.

In the next post, I get to see one of the incredible iconic sights of a Colorado River trip.

The Abandoned Lands...A Journey Through the Colorado Plateau: I've looked at erosion from both sides now

I guess I will never be a songwriter for Joni Mitchell. But I like looking at the effects of erosion. Sometimes you see it from above, for instance by standing on the rim and looking into the depths of the Grand Canyon. Sometimes you see it from below, by walking through a place like the Narrows of the Virgin River in Zion National Park and looking up at 2,000 feet of sandstone walls. But sometimes there are places where you get to look at erosion from both sides.

That's where we are today, a wonderful trail that takes us first through a narrow slot canyon, and then climbs to the mesa top above for a look down into the depths. This is the next stop on our journey through the Abandoned Lands, the desert environment of the Colorado Plateau. It's probably not all that fair of a quiz, but who can tell us where we are today? It's a place that receives relatively few visitors despite the incredible scenery. There was only one other car at the trailhead before our six vans showed up. A few clues about where we are...

Notice the rocks in the walls of the canyon. It isn't the nicely sorted sandstone that we often expect when water has carved such narrow slot canyons. This is more of a conglomerate with larger chunks of rock embedded in a matrix of smaller clasts. Some of the rocks are huge, as can be seen where large boulders have fallen into canyon. The rocks contain lots of volcanic material, including obsidian fragments that are sometimes called Apache tears ("Apache" is not a clue, though).

I guess I should also admit that a nitpicker would argue that we aren't actually on the Colorado Plateau, being on the edge of the plateau on the margins of a rift valley. The lower valley provides enough of a difference in base level that erosion is very, very fast, so fast that canyon walls can't collapse fast enough to make gentler slopes.

How bad can flashfloods get here? We certainly didn't want to find out. In the picture below, the students are looking at some silt deposits in a hollow about 12 feet above the floor of the gully. That was the water level during a recent gully-washer. If you are caught in such a flood, there wouldn't be much you could do to save yourself. By the way, notice that a fault line cuts across the cliff face in front of the people.

How fast is the erosion in a canyon like this? The trees give us a clue. How old do you think the ponderosa pine might be in the picture below? It's rather tall, and has probably been growing for a century or more...

 Look what has happened around the roots....

So...where are we at? (OK, Nina??)

In the next post we will look at this place from above, and provide the answer if some of you don't figure it out first.

Bookends to a Storm: Longs Peak in Rocky Mountain National Park

The calm before the storm; Bear Lake and Longs Peak

Wouldn't you just know that we would decide to go camping in the middle of flash flood-producing storm at  Rocky Mountain National Park...

We had a gorgeous day strolling around an almost eerily calm Bear Lake, but in the late afternoon the sky opened up with a tremendous thunderstorm. We delayed setting up camp, and when we arrived later at our campsite, things were peaceful and the night skies clear.

The next day, the same pattern built up, a late afternoon deluge, followed by a break, so (having moved to a different campsite) we set up camp and lazily had dinner in Estes Park. When we got back, lightning and thunder were rocking the entire valley, and the skies were opening up with all manner of hail, rain, and wind. We found out there were limits to the "waterproofness" of our new tent, termed the Taj MaHayes by my students. We sat in the car for a few hours, and when things finally settled down, we sopped up the mess and dried off as well as we could. We found out later that the storm dropped inches of rain across much of the park and areas south (Breckenridge got nearly 4 inches overnight).

The morning after the storm

Morning brought a beautiful sunrise, and bizarre looking clouds over the summit of Longs Peak, the highest mountain in the park. There were lakes and new channels all over the campsites. The rivers we saw today were overflowing their banks, including the river in Moraine Park, and the Colorado in the Kawuneeche Valley. It's been a neat vacation....

Impressive video of Flash Flooding in Queensland

Check out this incredible video of flash flooding in Queensland, which came to my attention courtesy of Yorrike on Twitter. A couple of thoughts on the event: As I watched, I thought "why aren't these people moving their cars out of the way?". Of course, hindsight is wonderful, and one can't know how bad the flood is going to be until one's car is floating away. Then again, midway through the video, a fellow is seen moving his car, and I suddenly realized how unwise that could have been, given how easily the other cars floated away.

On a sedimentary note, at the end the cars display imbrication, which is something pebbles do in a stream that allows us to see which way water was flowing (a paleocurrent indicator). I can't tell if the cars are oriented correctly, but the similarity to the cobbles below is striking. This picture is from Andrew Alden's About Geology Page, and this link is a good place to find out about imbrication.

Postscript:
The person who posted this video notes the following on his Youtube page:
With the incredible exposure that my video is receiving all over the internet and media worldwide I would like to encourage you to donate to the relief appeals.

You can donate to the Queensland Government Appeal at: http://www.qld.gov.au/floods/donate.html

Or the Churches of Christ Care Queensland Flood Appeal here:
http://care.cofcqld.com.au/site/docs/...

Please pray for us. There are many people who are suffering through this.