GREAT SALT LAKE — A rare geological phenomenon is back at the Great Salt Lake State Park.
They're called mirabilite mounds, and they build up when sodium-sulfate-rich spring water hits the cold winter air, the state parks service says. They also are only visible when the lake level is below an elevation of 4194 feet.
The mounds are not made from ordinary salt, but mirabilite -- also known as "Glauber’s salt."
A ranger first found them in the park in October 2019. Geologists did some investigation and research, and they determined how they were formed.
The state park is offering limited tours of the mounds on Jan. 9,10, 23 and 24. The tours will be every half hour from 11 a.m - 4 p.m. Reservations are required ahead of time and can be made here.
Park rangers suggest wearing boots that are water-resistant or waterproof, as the tour may include walking through deep mud.
More information on the unique formations can be found on the Utah Geological Survey's website.