In the distant past Lake Bonneville covered a good sized part of Utah. It also extended west into part of what is now Nevada and also north into what is now Idaho. It is said to have been over a thousand feet in depth and was about the size of Lake Michigan.
There were no outlets for this lake and so it kept rising until the water level reached over 5000 feet in elevation and was able to breach a place called Red Rock Pass in Idaho where it began to flow down into the Snake River.
However the water quickly eroded nearly 400 feet of elevation from Red Rock Pass and caused much devastation and flooding in the area heading for the Snake River. It also caused the level of the water in the lake to drop drastically.
That drop and a diminished flow of water into the lake caused it to shrink over several thousand years. Because of the drop in water level there was no more outlet and the water just evaporated. The lake shrank and because it was from evaporation the salinity of that water grew and grew and grew and grew.
Salt and chemicals that came into the lake from the streams were left behind with the evaporation that was taking place. As the waters evaporated and the lake shrank the concentration of salt and chemicals became stronger and left deposits of salt on the areas where the lake had once been.
These deposits are still there in the form of flats and if you drive west from Salt Lake City on I-80 and look to the north it is possible to see these stretches of white salt, perfectly level, going for miles and miles. Nothing grows, no plants, no grass, no trees just white salt.
But the demise of Lake Bonneville has left remnants to remind us that it was here. The Great Salt Lake is a very definite mark that is still here and has been a source of wonder for years. Utah Lake further south is another remnant of that once great lake.
And the salt flats that stretch for so many miles to the west, all the way to the Bonneville Raceway where so many come to see who can go the fastest and possibly be crowned as the fastest driver on this earth.