Bixby Ice Cave

Useful Information

Location:	Bixby State Preserve. From Edgewood follow North Franklin Street, which becomes Fortune Avenue, for 3.5 km. In Bear Creek valley parking lot on the right side. Follow dirt trail east, cross the creek, then follow stone stairs to the cave entrance. (42.674363, -91.399590)
Open:	No restrictions. [2021]
Fee:	free. [2021]
Classification:	Lead Mine Ice Cave Karst cave
Light:	bring torch
Dimension:
Guided tours:	self guided
Photography:	allowed
Accessibility:	no
Bibliography:	Larry Stone (2008): Explore a Nature Lover’s Gem, Iowa Outdoors • JULY / AUGUST 2008. pdf A. Solem, E.L. Yochelson (1979): North American Palaeozoic land snails, with a summary of other Palaeozoic non-marine snails United States Geological Survey, Professional Paper 1072: 1-42.
Address:	Bixby Ice Cave, Bixby State Preserve, Iowa Department of Natural Resources, Wallace State Office Building, 502 E. 9th, Des Moines, IA 50319-0034. Edgewood Economic Development, 104 North Washington, Edgewood, Iowa 52042, Tel: +1-563-928-7036. E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1854	Bixby family settles on the land.
1926	land purchased by the Iowa Conservation Commission.
1970s	snail expert Allen Solum finds a small population of Iowa Pleistocene snails (Discus macclintocki).
1979	dedicated as a geological and biological state preserve.

Description

Bixby Ice Cave is actually named Ice Cave, but unfortunately this name is descriptive and not a proper name. And there are ice caves in the dozens, so it's impossible to keep them apart, and that's why we added the location to the name. And another problem is the "cave" in the name, as this site is obviously a mine, though even Iowa’s Department of Natural Resources, which manages the site, isn’t sure about what, if anything, was ever mined there. Actually the rock is limestone, and it is karstified with caves and sinkholes. So this was most likely a rather small natural cave, which was widened by the miners of the 19th century. Some sources talk about lead miners, but there never was lead ore in the cave. Why they did this is unclear, because there are no ores or minerals left, which could have had economic value. Except probably the limestone, but it's much easier and cheaper to quarry limestone. In other words the origin of this tunnel is an enigma.

In the front of the tunnel a cold wild blows out, forming fog on warm days. The inside of the tunnel has thick layers of ice on the floor, between early spring and summer at least. Unfortunately it cannot be experienced directly as the tunnel is closed by an iron bar gate. We are not sure if it protects visitors from falling rocks or bats from the visitors. Legend has it that the mining effort was abandoned because too much ice formed in the mine. This was probably the most valuable thing in the tunnel, a century ago it was mined to cool ice cream and beer.

The tunnel is located in a talus slope in the valley of Bear Creek, which carved its bed into karstified dolomite and limestone. The rock is full of fractures and small caves, mostly a result of karstification, but probably also of earth movement at the slope. Those fractures form a network which connects the slope and the surface, in other words it has entrance at higher and at lower elevation. Temperature differences create a convection through the cave system. In winter the air in the cave is warmer than outside and the warm air leaves the entrances on the plateau, while cold air from outside is drawn in at the slope. In summer the cold and heavy air in the cave flows out through the debris of the slope, while warm air from outside is drawn into the dolines and crevices on the plateau. In other words, the talus slope is heated in winter and cooled in summer. Plants are growing during summer, and in this time the area is colder than the surroundings and thus has other plants, which are adapted to colder temperatures. Biologists call this an Algific Talus Slope.

This fact is quite important, it explains how snail expert Allen Solum found a small population of Iowa Pleistocene snails (Discus macclintocki) near the ice cave. Thought to have been extinct for thousands of years, the animal survived in Bixby thanks to the algific microclimate of the talus slope around the ice cave. Such endangered species are the reason why it is not allowed to leave the trails at the reserve.

Bixby State Preserve is named after R.J. Bixby, a teacher, farmer, and legislator. He owned some land at the end of the 19th century and began buying additional parcels to protect it from development. Bixby allowed the public to travel through his property free of charge long before the land became public, because he wanted to share the beautiful scenery with anyone who had an interest. He was interested that the land became a State Park, and finally it was purchased by the Iowa Conservation Commission. The park is basically the valley of Bear Creek, a tributary of Turkey River, and its slopes plus a narrow stripe of surrounding plateau. The preserve stretches east to west along the creek. The gravel road to the park is not maintained in winter, and actually it makes no sense to visit the ice cave in winter.