Monday, December 05, 2016

Fifty Years Ago This Week the Great Floods Roared Down Crystal and Bright Angel Creeks

December 5, 2016

Anniversaries are something I tend to notice and I'm so glad I did not let this one slip by unnoticed. It was fifty years ago this week that a four-day storm moved through the greater Southwest leaving between 11 and 14 inches of rain in about a 76 hour period. The intense rainfall produced what the United States Geological Survey called a 1,000 year flood. The following article appears in the current issue of the Boatman's Quarterly Review and I am happy to share it with readers today so they too can imagine what occurred here just fifty years ago. The flood is an integral part of the lore and history of river running in Grand Canyon since it created one of the top three rapids on the river (Crystal Creek) and destroyed the Transcanyon Pipeline just months before its completion.


REVISITING THE GREAT CRYSTAL CREEK FLOOD FIFTY YEARS LATER

December 3 to 7, 2016 will mark fifty years since a giant flood roared down Crystal Creek (and many others) in the Grand Canyon. Nothing like it has been observed ever since and as we mark this historic anniversary, I thought it would be nice to set the record straight on what is known and what is not known about this great flood. We all know that Crystal Creek Rapid was enlarged to become one of the “big three” rapids in Grand Canyon. But through the years, enough rounds of “telephone” regarding the dimensions of the flood, what was affected, and how much water was involved, have perhaps obscured what really happened. Data for this flood comes from USGS Professional Paper 980, published in 1977 by Maurice Cooley, B. N. Aldridge, and Robert Euler (Euler contributed results regarding the effects of the flood on archaeological resources).

The storm that produced the flood was regional in scope and affected all of southwestern Utah, southern Nevada, northern Arizona, and southeastern California. Each of these four states saw major flooding and although the North Rim area received the most precipitation at Grand Canyon, not all of the drainages between Saddle Canyon and Deer Creek felt the brunt of this powerful storm. The South Rim also did not receive as much precipitation, just ten miles to the south. At the time of the storm, there was very little snowpack on the North Rim. There was zero snow on the ground at both Grand Canyon Village and at Jacob Lake, and only an estimated 4 to 6 inches blanketed the ground on the North Rim in early December and only a trace of snow fell during the storm. The last significant precipitation before the December event was on November 8 and 9, 1966 and it can be inferred that at the time of the big rain, the ground was moist but not completely saturated.

The storm moved in from the southwest and drifted northeast across the region. Precise rainfall data for the North Rim were not available because it had closed for the season in early November and the rainfall gages were not routinely monitored. There were two gauges in 1966 – one at the North Rim Entrance Station (about 13 miles from the rim) and the other at Bright Angel Ranger Station (near the rim where the administrative area is today). At the Entrance Station between November 1 and December 7, 1966, 17 inches of rain had fallen. NPS personnel estimated that a maximum of only 3 inches was from the prior November storm and that the remainder - 14 inches - is the amount that fell during the December storm. At the Ranger Station on the rim, the gauge was not read between October, 1966 and May, 1967 but it held about 83% of that found at the Entrance Station gauge. This means that between 11 and 14 inches of rain must have fallen on the North Rim during the December flood. This is a good number to use on your trips when describing the flood. 


Ranger John Riffey was monitoring his gauge at Toroweap Valley and he reported that precipitation started at 1 AM on December 3 and continued through 9 PM the same day (20 hours of rainfall). After a 21-hour break, it started again on December 4 at 6 PM and, with the exception of only three hours, continued non-stop until 4 AM on December 7, making for 55 hours of rain in a 58 hour period! The total measured precipitation at Toroweap (elevation 4,775 ft.) for the five-day period was 6.05 inches – nearly equal to the full year average of 6.8 inches. Since Toroweap is a bit west of the North Rim and a lot lower in elevation, it is surmised that the most intense rainfall over the North Rim drainages likely fell between December 5 and 7 and that any perceived lack of certainty regarding the precipitation data from the rain gauges is probably near to being correct at 11 to 14 inches. 

Flood damage was reported from a series of after-storm reconnaissance missions in the canyon. Four distinct areas were shown to have high runoff. The first was a 5- to 7-mile-wide area running from Crystal to Nankoweap creeks, including not only Crystal and Bright Angel creeks, but also Clear Creek, Lava Chuar, and Kwagunt basins. Curiously, Unkar, Vishnu and Saddle canyons showed little evidence of high runoff, as well as the Crystal drainage on the rim and the upper portions of the Bright Angel drainage. This suggests that much of the precipitation likely fell within the canyon rather than on top of the rim (although certain drainages on the rim did see heavy flooding). The other three zones with significant evidence for extreme runoff were the Modred, Merlin, and Gawain Abysses in Shinumo Creek; at the North Rim Entrance Station where Shinumo Creek, Bright Angel Creek, and North Canyon Wash converge; and near the Cocks Comb at the head of North and South canyons.


Estimated maximum discharge was calculated for various side canyons: North Canyon Wash saw 800 cfs; Nankoweap, 3,000 cfs; Kwagunt, 1,200 cfs; Bright Angel, over 4,000 cfs; . Shinumo Creek, 2,000 cfs, and Crystal Creek, at over 30,000 cfs, with the vast majority of this coming out of the Dragon Creek arm. Mud- and debris-flows were reported in many of the side canyons, as well as severe lateral and downcutting erosion in numerous stream channels. Flow within Roaring Springs was also affected with a measured discharge on December 9 of 150 cfs (baseline flow is about 21 cfs). NPS personnel reported that water emerging from the spring was red and muddy on December 7, turning to yellow on December 9. The pump house at Roaring Springs was damaged when 2 ½ feet of water ran through the building and the Powerhouse just downstream from there (where the operator lived) was destroyed. In the 1977 USGS Professional Paper, it was reported that the flood washed out the trail in Bright Angel Canyon and “a $2 million pipeline” along Bright Angel Creek, and that “3 ½ years and an additional $5 million were required to rebuild the pipeline and repair the trail.” Severe damage was reported at Phantom Ranch as well, although the buildings here were no more than about 44 years old at the time of the flood.


However, archaeological sites nearly 1,000 years old were affected by runoff from the flood as well. In Clear Creek, the side of a mescal pit was breached and destroyed by channel erosion. It was also reported that in Dragon Creek (one the two major tributaries of Crystal Creek) that the 1966 flood might have been the largest in this drainage since the Pueblo abandonment in about 1150 AD. This is where an 8½ by 11-foot diameter mescal pit (and not a dwelling site as is commonly heard) was completely obliterated by a mudflow. It was not known if the mescal pit was merely covered by the mudflow or eroded away entirely. William Wallace Bass’s Shinumo Gardens largely escaped the highest runoff levels in the flood but the water did flood the area where his gardens used to be.

At this time, let’s remember the storm 50 years ago that continues to affect our lives and those of anyone who runs Crystal Creek Rapid. In summary, about 11 to 14 inches of rain fell within a three to four day period, on no more than six inches of snow. Crystal Creek saw an amazing 30,000+ cfs and Bright Angel Creek over 4,000 cfs. Two mescal pits were affected and one was obliterated completely. May we all live long enough to see another one of these fantastic storms!

Saturday, November 12, 2016

The Rocky Mountain Association of Geologists Honors "Carving Grand Canyon" with the Geosciences in the Media Award


Tonight, at the Rocky Mountain Association of Geologists (RMAG) annual banquet at the Warwick Hotel in downtown Denver, "Carving Grand Canyon" will be honored with their Geosciences in the Media Award. I received their most welcomed letter on August 30, informing me of the award. Of course, I was thrilled to receive the news.

"Carving Grand Canyon" was first published in April, 2005 and is now in its 2nd edition (2012). As of September 30, 2016, there have been 38,677 copies sold (two editions combined), with an additional 146 e-books sold since 2014. The 40,000 copy likely will be sold sometime around May 1, 2017.

Copy of the award letter send by the Rocky Mountain Association of Geologist
This award follows on the heels of the same award given in 2014 by RMAG to my other book, "Ancient Landscapes of the Colorado Plateau," co-written with Dr. Ron Blakey. You can view the entire list of recipients of the RMAG Geosciences in the Media Award on their web site here.

If you would like to order a specially signed copy from me personally, please click here. If you would like to order a book directly from the publisher, click here.

Thursday, November 10, 2016

Lake Titicaca, Peru

My last stop on this long trip around South America was at Lake Titicaca - long a goal of mine to visit. This tectonic and erosional basin located on the Altiplano is huge and straddles both Bolivia and Peru. We had great weather for our visit.

We arrived at our hotel in the dark so it was quite a surprise and impressive to look out in the morning and see red sandstone along the lakeshore. And tilted no less!

Tafoni in the sandstone. These are early Tertiary sandstones (as far as I can tell from searching the literature) and belong to the Puno Group, specifically the Saracocha Formation.

Cruising along the lake shore reveals the nature of the sedimentary rocks. Here they have given way to grey limestone.

More grey limestone along Lake Titicaca.

We took a hour and half boat ride to one of the floating islands that the Uros people near Puno live upon.

A Uro man came out in one of the finely crafted reed boats to greet us.

The totora reeds are used for many things - homes, "land," boats, baskets. But I was surprised to learn they are food as well, stripping the outer green to the white inside.

A long knife onboard allows for harvesting of the reeds. The islands are made when large blocks of totora roots are cut during seasonal lowstands of the lake. When the lake waters rise, the cut blocks float and are then "harvested" away to deeper water areas and together with other block. They are then tied together (today with modern straps but previously with reed twine).

Approaching the floating island.

Tying up the boat. The ground was quite squishy underfoot.

No doubt this was a "show" for the tourists but there are numerous islands all around and most of them are the real deal.

Totora reed hut with solar panels (right). They do have electricity make by the sun to listen to the radio.

Colorful tapestry for sale. I'm so glad I have passed the age of "buying."

A woman exiting her hut. I took a lot of photographs as this is ripe material for photography. And we had a perfect day! The lake is at an elevation of 12,400 feet above sea level, making it the highest navigable lake in the world.

The next event on the lake was a visit to Taquile Island pictured here on its north side. This is an unusual island in that the local people have taken control of the amount and kind of tourism that occurs here.

We landed on a dock that was completed in July off this year and the brand new trail that led upwards to one of the farmsteads.

Rural gate on Taquile Island, Lake Titicaca.

The trail led to this hilltop location where we had lunch in a hut. View to the southwest toward out hotel, Titilaka.

Men weaving on the island.

The trail down to the dock where we finished out visit.

Looking south on Lake Titicaca toward the Bolivian side. This concludes my blog posting for the trip, "Cuba and South America." Thank you for reading!

Sunday, November 06, 2016

Flying the length of South America and La Paz. Bolivia

Whew! The trip in South America was quite hectic but being at home is no less so - just familiar terrain. Enjoy these photos from a seven-hour flight from the southern tip of the continent to La Paz, Bolivia.

This is Morro Chico (Little Rock) a volcanic neck about 12 million years old. There are four other necks nearby along the road from Puerto Natales to Punta Arenas. Volcanic necks are the remains of a volcano -specifically the root or conduit where the lava  moved toward the ancient surface,

In the air again! I love these flight. This time it was a scenic flight over the southern Patagonia region of western Argentina and eastern Chile. This is Lago Argentina, one of many glacially carved depressions in this part of the world. Some are filled with sea water (fjords) farther west and some like this do not have a connection to to the sea and are filled with fresh water.

This is the next big lake to the north called Lake Viedma. Note the spine of the Andes Mountains beyond and the large glacier spilling out of them toward the east. Clear days like this are very rare in this part of the world.

Zooming into Mt. Fitzroy. These towers are a beacon to rock climbers and it was in this area that Yves Chouinard got the idea for the name of his outdoor clothing company, Patagonia. The granite spires belong to part of the intrusive event that also occurred at Torres del Paine to the south of here.

This is quite a bit farther north in Argentina and these are likely kettle lakes. One of the big frustrations in these flights is that sometimes huge weather systems cause clouds to block our view and we miss seeing huge swaths of the landscape. This si not so far north that the glacial evidence in Patagonia is is completely behind us however.

Another set of clouds obscured our view, I gave a lecture and by the time I returned to my seat we flying past Anconcagua, the highest mountain in the world outside of Asia, and thus the highest peak in the Western and the Southern hemispheres. It lies entirely within in Argentina but we are flying over Chile and looking to the east. Winter snow still blankets the lower elevations beneath the peak.

Just off the coast of northern Chile and southern Peru I spied the edge of huge band of clouds that stretched in the Pacific Ocean as far as the eye could see. Note the shadow cast by these clouds on the Pacific. As we landed briefly in Lima Peru, we descended through the cloud layer and when I asked our Captain how high was the blanket he told me it was 2,500 feet above sea level. The distance from the cloud to the sea here is 1/2 mile.

The next morning we were exploring the capital city of Bolivia, La Paz. What a truly unique setting for a city of two million people.

This area is right in the city and is called the Valle de Luna (Valley of theMoon). These are relatively recent volcaniclastic sediments (rocky debris and dirt composed of volcanic rocks) that is being rapidly eroded.

A hoodoo capped by a boulder in the Valle de Luna in La Paz Bolivia.

Look at the city as it grows up the slope of this giant arroyo cut into the edge of the Altiplano. The plateau top here is the edge of the Altiplano and the city has grown up onto and beyond onto the plateau.

Dense city cluster to the top of the Altiplano. The part of the city of La Paz on top is known as El Alto.

Growth of the city over the unconsolidated sediments. See an interesting article here about La Paz.

Mount Illimani at 21,122 feet above sea level is a dramatic backdrop to the city.

The national soccer stadium where many a South American football player comes to gasp for air. The stadium is at about 11, 932 feet above sea level.

La Paz does have a Colonial-era heart and the narrow streets are like many in South America.

The Plaza Mayor in central La Paz with the traditional flag (barely visible) behind the newest flag of the country, called whipala, which represents the loose amalgamation of indigenous nations. Seean interesting story behind this flag here.

Look closely at the clock on this government building - it is backwards with the 1, 2 and 3, o'clock hours on the left side. More background on all of this here.

Colorful street scene in old La Paz. The wall art is incredible and this man sleeping next to it was too rich to pass up.

An Amarya woman walks past the wall art.

Weaving seen in the store of a street vendor. It is a very colorful city.

A series of telefericos (gondolas) are part of the public transport system and we got to ride one to the top of the Altiplano. An interesting solution to the horrific traffic that clogs the streets.

Fantastic clouds seen on our way to Lake Titicaca across the Bolivian Altiplano. This was a dream come true for me to visit the lake and see the Altiplano. My last blog posting from this trip will be about the lake.