A dude asked a voodoo how hoodoos were formed. “Who knew,” the voodoo answered, “Who knew?” We now know and the voodoo dude will know soon too.
Hoodoos are geological formations found in arid areas of the Great Plains and Southwest Deserts of North America. The Montana hoodoos we will focus on originate within the Marias River watershed – the Jerusalem Rocks of Sunburst, Little Jerusalem south of Sweetgrass and then the magnificent Rock City north of Valier.
First, let’s answer the voodoo dude’s question: how are hoodoos formed? Persistent, dry winds blow away the many layers of soil from the tops
and sides of hills and coulees, meanwhile the snow and ice break up the formations, with the runoff pulling the sand and slowly eroding away the layers of rock. Many badlands have been formed in this exact manner, but hoodoos carry something stronger that sets them apart. Atop each and every hoodoo is a stronger, harder rock that disallows erosion from above. The characteristic orange or red lichen grows atop these hard surfaces, but the heavy metals within also give the rocks a reddish hue. The rain and wind swept sand cannot erode the hard iron caps each hoodoo wears, and so must erode the sandstone below. Slightly acidic rainwater further eats into and rounds off the sandstone hoodoo towers. Eventually the sandstone will fail, and the harder, stronger tops will fall; as evidenced by the avalanche of those red tinged rocks leading down the hillside.
Lining the edges of the Kevin Rims, the Jerusalem Rocks of Sunburst begin sprouting up several miles south of their densest population. The dirt road winds through a giant, 126 windmill installation and finally we turn west toward Sunburst, parking now for a short hike south toward the northern edge of the Kevin Rims. The sandstone rims can clearly be seen across the canyon, and it all frames the hoodoo outcropping known as the Jerusalem Rocks. From our vantage point we can easily see the West Butte of the Sweetgrass Hills, which is 25 miles away.
Little Jerusalem, located five miles south of the border town of Sweetgrass, has a similar name for similar sandstone structures. Traveling north from Sunburst, the Kevin Rim disappears, being replaced by smoother coulees and hillsides, yet the Huckleberry Creek has slowly cut a deep ravine into this landscape. The hoodoos here appear in greater number as the hills have been cleanly eroded away, giant walkways of rounded sandstone leading to the clusters of orange topped hoodoos. Much easier to get to, Little Jerusalem road cuts right through this hoodoo cluster.
The Birch Creek enters the Two Medicine River about 15 miles straight north of Valier. For about a mile in either direction, up or down the Birch or Two Medicine Rivers, one will be walking through the hoodoo city called Rock City. The Jerusalem Rocks were two small villages of hoodoos, and Rock City is a metropolis. Thousands of hoodoos populate this land. Giant mushrooms of rock and small towers of rock. A patch of hoodoos rise up to 15 feet from the floor below, but are so close together that one can easily run atop the hoodoos. Across the river, in every direction, sits hundreds more. Rapids exist below. If one wants to climb down, the canyon falls over 100 feet to that river bottom. Not even recognized as a state park, this area should be in consideration for national recognition, but in the meantime, the most frequent visitors here seem to be paintballers and keg partiers.
Hoodoos have stood the tests of time, through windy winters and windy summers, and like the people of Montana, still stand strong. The Jerusalem Rocks, Little Jerusalem, and especially Rock City, are amazing hoodoos of Montana that can be difficult to reach, but the beauty is unmatched and the visit is worth your time. The hoodoos are destined to fall, so go and see them before they erode away, in the next million years.