Photo of Rock City geologic formation in Montana

Weekly Gem #109 Hang on to your hat, if you visit Rock City

Published 3/11/2017

Location:  This 'hidden gem' is located about half way between Valier and Cut Bank, MT (as the crow flies, that is) Here's what I want you to do. It'll just take a couple minutes, and trust me, you'll thank me later. On a separate page, find "Rock City, MT" on a map, then come back and read the rest. Note that Rock City is on the southern bank of the Marias River, so the map pointer may not be exactly right. Find the Rock City icon on the map. You'll need to jump back and forth, so go ahead and open the map.

Zoom slowly until you can see the rock formations, called Rock City. Pretty cool.

But even cooler, is when you slowly zoom out, or if you pan along the Marias River, you see that this is the only place where these formations show up. There are a few on the north side of the river, this dense cluster on the south side, and that's it. What the heck is going on?

Well, I'll tell you. This is one of the windiest places in the U.S., and the prevailing wind is from the west, 12 months of the year. The "wind blown look" is the only look.

Now, look at the map. The river you see flowing west to east, the Marias, is about 100 feet below the Rock City formation that is up on the cliff top. That river is very twisty and turny over most of it's length, but about a mile west of Rock City it straightens out. Now, all that wind blowing across the prairie starts to drop into the canyon, making it a natural wind tunnel. "Wow, this is pretty!" says the wind. Then BAM! It hits the point where Birch Creek flows into the Marias.

Look at how Birch Creek flows into the Marias from the south just at the west side or Rock City and, how that confluence made the canyon wall suddenly turn north. The happy Chinook wind that was enjoying the scenery is suddenly and violently compressed as it rips over the top of that cliff, taking bits of dust with it. After a few thousand years of sand blasting, we have Rock City.

In fact, if you look at the west side of Rock City, you can see deeper gouges where the wind was really humming. The carving continues as the wind moves east across Rock City, until it drops off the edge of the cliff, and can again enjoy the scenery.

.........

Here's the hidden gem entry from our Clue Me! map.

Clue

The wind blown look (accessible by car, barely, and preferably with the top down)

Description

Rock City

Why It's Interesting

Something about this small point of land led to the creation of these interesting rock formations. The top layers are harder than the bottom, allowing the wind to scour the bottom layers out, leaving behind lots of interesting formations. The rock formations are interesting. The question of 'why here?' is as well. There's a lot of river, a lot of canyon, but only a small patch of these formations.