Kepp’s Crossing Overlook Slope Site – Idaho Slope Soaring Site

Kepp’s Crossing Overlook Slope Site

Cory sent in this great report on a slope soaring spot in Southeast Idaho. He says Idaho Falls is at the eastern end of the Snake River Plain. This plain is oriented generally in line with the jet stream in spring and fall, which helps produce our winds.

Southeast Idaho has a reputation amongst its residents for being pretty windy. I’ve lived here for 29 years and always thought so too, that is until I took up slope flying in the early ‘90’s. Sometimes it seems like the wind only blows when all of my planes need repairs. Murphy must have been a sloper!  Seriously, I once knew someone who moved here from “The Windy City” who claimed that Chicago was calm compared to here.

Idaho Falls is at the eastern end of the Snake River Plain. This plain is oriented generally in line with the jet stream in spring and fall, which helps produce our winds. Unfortunately, most of the steeper slopes in our area do not face the prevailing wind direction of SSW.  Fortunately there are several exceptions. I will submit descriptions of these sites as I fly them this spring.

This part of the cliff makes the best lift.

My first flight of this spring (March 19th, so actually the last full day of winter) was at the Kepp’s Crossing Overlook. This slope site is in the foothills about 16 miles east of the Idaho Falls area. Kepp’s Crossing is a bridge over Willow Creek.  The flying site is a lava bluff that sits about 350 feet above Willow Creek, about a half mile from the bridge. The hill rises steeply for close to three hundred feet, and then is capped with a 60′ sheer lava cliff. Hawks, swallows, crows, and occasionally pigeons are frequent soarers here. A couple of years ago 43 very large wind turbines were installed a few miles west of Kepp’s.  This site was chosen because of its consistent winds. The winds aren’t quite as consistent at Kepp’s, but they’re still good. It’s almost always windier at the cliffs than down by Idaho Falls. This is high desert country with sagebrush, prickly pear, and an occasional rattlesnake.

Me and my plane on the edge of the cliff.

I took a friend, Blaine, a powered RC pilot who I am introducing to slope flying, with me on the 19th. I’d estimate the winds were usually 10-15 mph on this trip, although they occasionally dropped to 5 mph or less. The plane I was flying was my own design, “Plane in a Day”. That’s how long it took me to build it. It’s a 36″ foam and tape plane based on the old “Anabat” design, even using the ailerons and horizontal stab from my old Anabat, with the symmetrical airfoil replaced by a Don Ayres 7518, a solid spruce leading edge and sub trailing edge, and a sleeker nose. On this day the plane flew decently, but 6 times the wind speed dropped low enough that I couldn’t maintain lift. Remember, though, that this is a small plane with an untapered wing.  I’m sure I would not have had any problem with a 60 inch wing span. Once, I missed getting back on top by about two feet, slamming head on into the cliff and tumbling down. Fortunately no damage occurred to the plane. Access to the hillside at the bottom of the cliff is easy. You can easily scramble down a sloped area between the two parking areas, and also at a cleft in the cliff 200 or so yards to the south of the place I like to launch from. Tuesday evening the wind was considerably stronger, so I went back.  This time the lift was strong enough that when I launched, the plane immediately took an elevator ride up about 100 feet. Lift was no problem. I should have added ballast, but this plane penetrates pretty decently for its light weight and inefficient short, square wing.

The landing zone is very flat. It’s about 150 yards square with no obstruction except for a small pile of rocks about 2 feet tall and 15 feet wide. In the area where most people park, the dirt has been worn away and it’s pretty rocky.  About 40 yards back, or to the south, the landing area is much softer, with dirt over the lava and some light CRP grass. To the south, after you pass the first few clumps of sage brush, you will find more room for landing.  On a windy day there are some pretty strong rotors in the landing area, and especially about 100 yards back from the rim. Keep some altitude as you circle around to set up your landing so that you can carry some speed on final and punch through the rotors.

Looking back toward the cliff over the 150 yard landing site.

A week later, Blaine, and I went back to fly again. This time the wind was strong, probably 25-30 mph, but it was coming from the south-southeast, which is not a common direction for the wind here. There is an easy to find two-track that takes you to the rim around the bend of Willow Creek to the south and southeast of the main flying site. The canyon runs pretty much east to west here. In this area, there really isn’t much of a cliff, maybe 10-15 feet in some areas. The canyon is narrower also. This seems to create more turbulence than at the primary flying site. I found a couple of areas of concentrated lift that really helped get higher half pipe pumps. After flying for about 25 minutes I added some ballast to the plane by taping a pair of pliers under the CG. This made a noticeable increase in speed, probably 10-15 mph in level passes, and helped tame the turbulence. Landings in this area are all in sagebrush and grass.  I have never flown this part of the slope in light winds.

The strongest wind I’ve ever flown in at the main site was about 40 mph.  The lift was awesome!

Looking off the cliff towards the prevailing wind. Willow Creek is 350′ below.

There are two ways to get to the Kepp’s Crossing flying area. The first is via Sunnyside Road on the south side of town. From the intersection of Sunnyside and 45th E., zero your trip odometer, then go East 8.4 miles to the intersection with Bone Rd.  Turn South.  In approximately .2 miles leave the pavement by turning left (east) on Eagle Pass Road. The dirt and gravel roads in this area are pretty well maintained.  At 10.9 miles you will come to a “T” intersection with Kepp’s Crossing Rd. Turn right. You will cross Willow Creek at Kepp’s Crossing.  Continue up the hill to 12.7 miles on your odometer. Immediately at the top you will see a flat area that is good for parking.  Pass this one up and pull in to the next one about 100 yards later.  You can drive right up to the edge of the cliff.  Please take care of this property so that we can continue to use it. Some people have unfortunatly thrown things like refrigerators, a truck, etc. off the cliff.

The second way is via Lincoln road on the north side of Idaho Falls. Zero your odometer, then go east, climbing the foothills. Shortly after cresting the first hill, at 4.5 miles, you will descend to the intersection with Bone Rd.  Turn right.  At 11.4 miles you will come to Kepp’s Crossing Road. Turn left. At 14.3 miles you will come to the flying spot. As you drive through the canyon area of Kepp’s Crossing Road you are driving under another good flying site that will be a subject of a latter article I’ll send in to Greg. That site appears to be good for DS, although I don’t know how to do it yet so I haven’t tried.

Here’s a Topozone link to the main flying site

The site I used on the day of the rare SSE winds is here

In the rare instance of a North wind try here

If you have any questions you can PM me at RC Groups. My ID there is “Cory”. You can also e-mail me at but I’m on RC Groups more often than I check my email.

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