GC1JMH8 Big Thompson Canyon Flood - Climb to Safety!
Type: Earth | Size: Other | Difficulty: | Terrain:
By: Me & Bucky @ | Hide Date: 12/03/2008 | Status: Available
Country: United States | State: Colorado
Coordinates: N40° 24.610 W105° 23.249 | Last updated: 08/30/2019 | Fav points: 0

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This EarthCache will take you to a location where the effects of the Big Thompson Canyon Flood can be seen. At this site a boardwalk has been built and fish habitat has been reconstructed in a cooperative effort between the U.S. Forest Service, Colorado Division of Wildlife, and several private organizations. This EarthCache is wheelchair accessible through the use of the ramp which is located on the east end of the parking area. GPS reception is poor in the canyon, and can be off by significant fractions of a mile. Therefore, parking is at an asphalt pulloff on the south side of the road at mile marker 72.

Big Thompson Canyon Flood

The Big Thompson Canyon Flood occurred on July 31, 1976. Between approximately 6:30 pm and 10:30 pm, a thunderstorm stalled in the mountains in the upper reaches of the Big Thompson Canyon. Between 10 and 16 inches of rain fell in 4 hours and this caused the river to flow at an estimated 31,000 cubic feet per second (cfs) in the main river below the town of Drake. For comparison, this is over 150 times the normal flow of the river, which is 200 cfs. The resultant flood tore through the canyon destroying homes, businesses, roads, utilities, and the Loveland power plant at Viestenz-Smith Park. The depth of water in some parts of the Narrows was 20 feet; 17 feet deeper than the normal summer depth of 3 feet. The flash flood, which caused damage as far away as the South Platte River near Greeley, took the lives of 144 people. This is considered to be the greatest loss of life due to a natural disaster in Colorado’s history.

New Fish Habitat

Take the steps or ramp down to the boardwalk, then head right for about 50 feet to the west end of the boardwalk. Notice the large granite boulders just upstream and in the center of the river at this point. During the flood, with the river running at over 31,000 cfs, the force of the water was such that boulders this size would have easily been carried down the river. As part of this stream improvement, these rocks now serve to break up the flow of the current and create new habitats in the river. If you look at the boulder in the center of the river, the flow is split and runs on each side. The river then widens out and an eddy in the current is created behind the boulder.

To log this EarthCache, send me an email with the answers to the following questions: 1.) Compare the depth of the river on each side of the boulder versus the depth in the eddy. 2.) Similarly, compare the size of the rock material on each side of the boulder versus the material in the eddy. 3.) What should you do if you are in a canyon during flash flood conditions?


Please consider posting photos of yourself, or the local geology, when you log this EarthCache. Photos can be an additional rewarding part of your journey, but posting them is not a requirement for logging this EarthCache, and is strictly optional.


The above information was compiled from the following sources:

Informational plaques from several memorial sites along the Big Thompson Canyon.

2006. Jarret, R.D., and S.J. Vandas. 1976 Big Thompson Flood, Colorado. USGS Big Thompson Watershed Forum. Big Thompson Canyon Association. USGS General Information Product 35. Online at: http://pubs.usgs.gov/gip/2006/35/pdf/GIP-35_screen.pdf

1996. Gruntfest, E. What We Have Learned Since The Big Thompson Flood. In: Twenty Years Later: What We have Learned Since the Big Thompson Flood. Proceedings of a Meeting Held in Fort Collins, Colorado, July 13-15, 1996.

Thanks to the Roosevelt National Forest for allowing placement of this EarthCache!

06/21/2019 By Cache Couple 2
We started our journey today from Estes Park to Fort Collins following the big Thompson River. What a fabulous drive it was following the river through the canyon. From there we headed north to Cheyenne and up to Curt Gowdy state park. Along the way we stopped to do some geocaching. TFTC

05/14/2019 By Diz&Dave
Greetings from the UK?. We are on our holidays!!! We are on a 12-day road trip around Colorado, Utah and Wyoming (a geocaching road trip from Denver to Yellowstone and back again), staying in Air BnB’s en route. Day 1: One cache near the first Air BnB to get us started Day 2: Morning caching around Denver and then headed out on the Mount Evans scenic route ?Day 3: Denver to Colorado Springs, collecting a few caches en-route. Made a snap decision to head out to collect some earthcaches , discovered the amazing Garden of the Gods , Manitou Springs, and the lovely Memorial park. Day 4: A trip up to Pike’s Peak and then a slow cache and dash to Glenwood Springs ? . Day 5: Cached to Vernal via Craig and a scenic drive through the National Dinosaur Monument to Harper’s corner . Day 6: Set off from Vernal, visited the brilliant National Dinosaur Monument , then drove the scenic roadway to Rock Springs, more caching en-route. Day 7: Today was Wildlife Day! Rock Springs to Jackson, and the Teton National park. We saw: Pronged antelope, 2 Moose(s), Bighorn Mountain, Elk herds , an osprey . Day 8: The day we saw three bears !! to West Yellowstone, collected a cache in Idaho. Arrived Yellowstone late morning and had a fantastic time in Yellowstone , amongst the Bison. We had a lot of snow showers???. We watched Old Faithful and did lots of of geography homework earthcaches and virtuals . Day 9: A great morning exploring Yellowstone Park -tastic and loved the stroll around the mud pots. On the long, slow drive to Lander, were we spotted Pronghorns and Mountain Sheep – in the road! We did some caching en-oute, as well as stopping for some chocolates from the Cowboy Chocolatier in Meeteetse. Day 10: Today we met up with a local cacher, who had kindly offered to show us the sights/caches of Lander. And… had an amazing day, not only did we pick up some fun caches, we walked some beautiful trails, in great company and learnt a lot about the local history. Original Wildman was incredibly generous with his time and his hospitality. Day 11. A cache and dash to Cheyenne via Laramie, saw lots of Pronghorns and Jack rabbits , collected 23 caches and spotted some very large cowboy boots in downtown Cheyenne.
Day 12: Our penultimate day, and last full day started with a great breakfast at Epic Egg ,we then started the drive to Denver, with a final epic days caching as we had several challenge caches to pick up (with great D/T ratings) and some by Egreog, as his came recommended by the Original Wildman . We also decided after a morning urban caching to take a tour out to Estes Park , and collect some of Bug Rangers’ very creative caches . This meant that we arrived at our BnB quite late, but our hostess was amazing, and we then headed out for a late dinner, minding Meadowlark, which had fab food, and now pack to pack and log, before a last morning in downtown Denver – 38 caches in all today.

Dave has emailed the CO with our answers.
TFTC ?

03/24/2019 By Dud&Plato
Had to add to the fun of a great day running around Estes with a stop here on the way back. An extremely pretty location that was nice to stop and enjoy for a while. Some snow in the area decided to leave us alone while we did, and that made it all the nicer. Took several photos to help aid in answering the questions as specifically as possible. Nice to see a new deck here as well! Email with answers has been sent to the CO. Thanks for a reason to stop here an take it all in!

03/24/2019 By BriaTeragram
Made a stop to do this EarthCache on the way home from Estes. This is my first EarthCache. It's nice to see the new boardwalk going in after the most recent flood. Stopped with Dud&Plato. TFTC

08/21/2018 By korriaan
Traveling through on a major trip out to Washington and seeing the sights between St. Louis and Seattle. Such amazing places to see! Thanks for the Earthcache - they always make a trip just a bit more interesting.
Answers sent.

06/29/2018 By zanna
Out from Atlanta exploring Colorado with FLtravelers for a few days. He was able to finish all his counties, while I made more progress on the state. Lots of fun caches were found along the way, including this one.

TFTC

06/29/2018 By FLtravelers
Flew out to Denver with zanna to grab a cache in the smattering of counties I had left in Colorado. Along the route we stopped for highly favorited caches, virtuals, earthcaches, webcams, Colorado's oldest, and whatever else that looked interesting. This was certainly one of these. Great spot. TFTEC.

09/23/2017 By cvSCRAT
On the way to Greeley with Rositagal93 and Casey and we stopped for this cache. An email and/or a photo will be sent or posted. TFTC #13298

08/28/2017 By Milek78
Touring around the Colorado and neighboring states with Bone. Today was the day to visit the Rocky Mountain National Park and finding few Earthcaches and Virtuals. Another one on our way back to civilization. Such a tragedy...Hard to believe this much water in the valley. Thanks for bringing me here.