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Water courses at TatahatsoBeach

Fatal Debris Flow at Tatahatso Beach, Grand Canyon, 14 July 2021

The summer 2022 issue of the Arizona Geology Newsletter, V43, #1 is available online.

The chief article, “Get to the Boats! Fatal Debris Flow at Grand Canyon’s Tatahatso Beach, 14 July 2021”, describes a singular debris flood/flow event that sent 32 whitewater rafters scrambling for their lives. This occurred at Colorado River mile 37.9, just downstream from Tatahatso Wash in Grand Canyon National Park. The debris flood was fueled by a torrential monsoon storm which dumped ~ 1.25 to 1.75 inches of rain between 5:00 and 5:40 p.m. Rafters setting up camp on Tatahatso Beach were overwhelmed by a debris flood that fell ~400 feet from the overhanging Redwall Limestone - see image below. One person, Rebecca Copeland, was killed and several other people were seriously injured. Guides and guests were evacuated the following day by Grand Canyon National Park rangers to receive medical care.

The article includes 12 figures, a graphic deconstructing the events of that day and the following day, and a link to a two-minute long video capturing the latter part of the flood event.

Other newsletter highlights, include:

i. New AZGS Basin Analysis Research
ii. Short notes on five upcoming AZGS projects:
    a) Geologic mapping (NCGMP);
    b) Data preservation & critical minerals activities (NGGDPP);
    c) Geochemistry of Laramide Porphyry belt;
    d) Holocene mapping Lower Little Colorado River;
    e) Reducing impacts of post-wildfire floods.
iii. AZGS publications released in 2022.
iv. AZGS Social Media Update.

Direct link to newsletter 


Figure 6 - firehose
Debris flood falling on Tatahatso Beach from an overhang 400 feet high. Photo by LA Robinson.

J.P. Cook edited Arizona Geology Newsletter Summer 2022.