You are standing in an area that was once covered by the waters of Lake Bonneville. Lake Bonneville was a large lake (approximately 20,000 square miles) that covered a large portion of Western Utah and Eastern Nevada, and a smaller portion Southern Idaho. About 16,800 years ago, the lake crested Red Rock Pass (near Downey, Idaho) and began flowing toward the Snake River. Researchers estimate that the lake level fell 375 feet in 1 year. Gradually, the climate grew warmer and drier, further shrinking the lake, finally leaving only a few remnants that we know today.
Looking to the south, a tall hill (Anderson Hill) is visible. Along the flanks of the hill, numerous horizontal lines are easily visible. These lines were the shorelines of Lake Bonneville. Two of the shorelines are easily visible: Provo (about 4,840 feet/1475 meters, from about 16,000 years ago) and Bonneville (about 5,220 feet/1591 meters, from about 18,000 years ago).
There is a powerline between the cache location and Anderson Hill. By moving forward and backward, you can use the powerline as guide to aid in identifying less distinct shorelines. How many shorelines can you find? This area is now a desert. Try to imagine what the area looked like 18,000 years ago when the lake water covered this location.
This cache is readily accessible from Interstate 84 Exit 24 (Valley). The stretch of interstate from Tremonton, Utah to Sweetzer Summit, Idaho (between exits 254 and 263) provides several good views of the "footprints" of Lake Bonneville. At Sweetzer Summit, elevation 5,530 feet, you leave the Great Basin (and Lake Bonneville) and enter the Snake River drainage. The road also crosses three small mountain ranges (Blue Spring Hills, North Promontory Mountains, and Hansel Mountains) that were islands in Lake Bonneville. From the higher passes along the route, the living remains of Lake Bonneville, The Great Salt Lake, is also visible.
Please note that this is a remote area. The nearest services are in Snowville (17 miles west) or Tremonton (16 miles east). Summers are typically hot with little rain. Winters range from mild to blizzard and white-out conditions. Under most conditions, this cache is easily accessible by passenger car and is handicapped accessible. If the ground is very wet, you may have to park your car and walk the last 200 feet.
To receive credit for finding this cache, you must physically visit the site and then email the answers to the following three questions:
1. What was the maximum depth of Lake Bonneville at the cache site (how far underwater was it)?
2. Approximately how tall was the island created by Anderson Hill when Lake Bonneville was at its deepest?
3. What was the elevation reading from your GPSr or smartphone? (Smartphone users may need to download an app to determine the altitude--search your app store for "altimeter".)
Note that there is no interpretive sign or marker at the cache location. You will have to use your wits (and possibly the cache hint) to answer the questions. Do your best and concentrate on learning about Lake Bonneville!
Note: groups finding this cache need submit only one set of answers but please include the names of all cachers in the group. Have fun and thanks for visiting!
Sources:
Commonly Asked Questions About Utah's Great Salt Lake and Lake Bonneville - Utah Geological Survey
Great Salt Lake, Lake Bonneville and Bear Lake - Utah Geological Survey
Idaho Road & Recreation Atlas, Benchmark Maps, 2005.
Utah Road & Recreation Atlas, Benchmark Maps, 2004.
Idaho Historical Marker #317, “Lake Bonneville”.
Idaho Historical Marker #171, “Red Rock Pass”.
Congratulations to pelt45 on the FTF!