Flood warning for Cataract Canyon, Supai Village

The Havasupai Tribe declared an emergency late this morning following an automated flood warning on Cataract Canyon. We have reports that a partial evacuation of Supai Village was underway in advance of the flood waters that should have hit around noon today.

The Tribe yesterday posted an announcement on their web site and tweeted that the campground would be closed for at least a week due to flood damage from the past few days. The Tribe reported evacuating 150 tourists on Sunday afternoon due to flooding through the campground.

Brian Gootee with the AZGS Phoenix office is in contact with tribal officials and plans on getting into the canyon tomorrow to help assess restoration and mitigation needs.

Vance Holliday: impact did not end the Clovis culture

UA professor Vance Holliday and his colleague have put another nail in the coffin for the hypothesis that an extraterrestrial impact at about 12,900 ybp in North America produced the end of the Younger Dryas climate and the Clovis culture. [right, a Clovis spear point can be seen in the center of the photo, lodged in the skeleton of a mammoth excavated by UA archaeologist Emil W. Haury at Naco, Ariz., in 1952. Credit, Arizona State Museum]

In an article in the current issue of Current Anthropology uses radiocarbon dates, geomorphological and archeological evidence to conclude that "an extraterrestrial impact is an unnecessary solution for an archaeological problem that does not exist."

A spate of recent studies have disproved evidence of the impact itself.

Ref: The 12.9-ka ET Impact Hypothesis and North American Paleoindians, Vance T. Holliday and David J. Meltzer, DOI: 10.1086/656015

FEMA faults Yuma levees

FEMA has revoked accreditation for 23 levees in Yuma County, Arizona as part of a nationwide reassessment of the flood prevention features, according to a story in USA Today. This means that affected homeowners will have to buy flood insurance. Another 260 or so levees in California were also de-accredited.

Mapping El Mayor - Cucapah fault rupture

The April 4, 2010 M7.2 El Mayor-Cucapah earthquake in Baja ruptured the surface for 60 miles (100 km) prompting a number of field studies. NASA's Earth Science Picture of the Day for Sept. 16 shows a team investigating the rupture:

In August, a team of geologists from CICESE (Centro de Investigación Científica y de Educación Superior de Ensenada), USGS, Caltech (California Institute of Technology) and other organizations spent five days mapping and measuring the fault. Much of this was done by flying teams in by helicopter and dropping them off along the main scarp. Water and emergency supplies were also brought in since it was hot -- 115 F (46 C) by mid afternoon. In this picture, the main scarp is seen along with three geologists. Here the scarp is about five feet (1.5 m ) high, dramatically attesting to the amount of energy it took to shift that much rock along many miles. Further from the epicenter, the scarps grew smaller, in some places being only 1 in (2.5 cm) in height. Photo taken on August 10, 2010.

Flooding prompts evacuation in Havasupai canyon

Our friends in the Havasupai Tribe report that flash flooding on Sunday afternoon forced evacuation of 150 tourists from the Havasu canyon campground. The waters came down a side canyon that did not have a water gaging warning system. It was estimated at about 1,000 cubic feet per second, comparable to a flood that hit the canyon in January. [right, aerial view of the new creek bed from 2008. My photo]

The worst flooding in a century hit the canyon in August 2008, which resulted in hundreds of camper racing to high ground in the darkness, buried the campground with many feet of sediments, and caused the creek to shift its course to the other side of the canyon. The Tribe is still dealing with the impacts of that dramatic event. The change of the creek bed may be partly contributing to the recent smaller floods affecting the campground and trails.

Paleogene river ran opposite to modern Colorado

A Paleogene river the size and scale of the modern Colorado-Green river system carried sediments from the Mojave region of California to Utah's Uinta basin for as long as 20 million years before tectonics reversed the regional drainage system. [right, space station view of the southwest U.S. Acquired 9-10-10. Credit NASA]

A new article in Geology, includes co-authors Bill Dickinson and George Gehrels at the Univ. of Arizona and AZGS Senior Geologist Jon Spencer. Lead author is Steven Davis from Carnegie Inst.

Ref: The Paleogene California River: Evidence of Mojave-Uinta paleodrainage from U-Pb ages of detrital zircons, Steven J. Davis, William R. Dickinson, George E. Gehrels, Jon E. Spencer, Timothy F. Lawton and Alan R. Carroll, doi: 10.1130/G31250.1 v. 38 no. 10 p. 931-934

Getting back in the blog saddle

There's a stack of blog topics on my to-write list almost as long as the emails stacked up in my in-box.

I've been on the road most of the past couple weeks - Washington DC with the State Geologists for 25+ meetings with federal agencies, Congressional committees, and NGOs; from there to Denver as a co-organizer of a 2-day NSF-sponsored workshop on building a National Geoinformatics Community, followed by a side trip to our family cabin in Wyoming (25 miles to the nearest cell phone access) before zipping over to Boise for the formal review of Phase 1 of the National Geothermal Data System project. A lovely 1100 mile drive home got us to Tucson just as the monsoon dropped the temperature 25 degrees at one degree per minute.

1200 emails but only 6 phone messages waiting for me, so if I haven't gotten back to you, give me a couple days to catch up. There are follow up actions from this flurry of activity that need to be pursued as well.

Got through the mail tonight and paid the bills, so I should get back to blogging. Thanks to everyone who has passed along news and links.