UNIMOG Colorado
Rocky Mountain Moggers
RMM Trip Report

December 26th, 1999 - Mt Evans Expedition #3, Colorado

Our primary goal as so well stated by Dr. Stencel of the University:

First and foremost: "RETURN SAFELY".

The purposes of this trip included a need to get to the summit observatory before more serious snowfall prevented servicing an out-of-trim situation with the solar battery supply, along with an excuse to show how Unimogs could perform in challenging conditions.

Unimoggers today were:

Tyson Pfenneberger from Parker, CO
Swiss 404 with 12k Warn winch
Christine doing their truck-trailer transportation

Rodger Greer and Daniel (son) from Monument, CO
Swiss 404

Fred Reim and Judy Gardner
404 radio truck

Bob Ragain and Dawn Jewell (daughter) Littleton, CO
404 radio truck

Our hosts were:
Dr Stencel, head of Astronomy Dept, DU

Chris Cudlip, student of astronomy and computer guru

Ken Thames, Thames Solar Electric (303-936-9377)

Peter McNutt, PV expert NREL

Dawn and I met up with Rodger Greer and son Daniel at the planned 0600 just west of Golden. Our climb up through Idaho Springs toward Mt Evans Road was rather uneventful. Even traffic was light due to this being 0600 on Sunday. We even had time for a McDonald's stop in Idaho Springs. The highway had some snow pack and ice above Idaho Springs, but it had been plowed and sanded.

We were first to arrive at the meeting spot a few minutes before 8:00, at the parking area at the entrance to Mt. Evans Road.

The parking lot had been plowed and this would make chaining up much more pleasant. Snow had been pushed up in a 6 ft pile all around the lot, including across the gate. The required shoveling was good practice for what was to follow.

Dr. Stencel and the University of Denver gang arrived soon, then Tyson and Christine arrived with their Mog on a trailer, already chained up and ready to go! That's the way to do things! Tyson had decided to join us at the last moment but his mog and winch really played a big part in this assault on the mountain.

Fred and Judy arrived just a few minutes later so our group was complete. We completed chaining up while Dr. Stencel and crew cleared the blocked gate enough for a mog to bust through the snow pile, and within about an hour we were ready to head up the mountain.

. .

In the first mile there was considerable snow on the road, averaging about a foot, but in some places as much as 3 ft. This was not the light fluffy stuff we shovel off our sidewalks! After many snow/thaw/refreeze cycles this "snow" becomes more like laminated ice. On flatter sections we could actually drive over it. When we reached more of an incline the tires and chains would dig through the snow to the road below.

. .

This stuff was able to support a Unimog resting on the differentials, causing the truck to bounce side to side as the chained tires grabbed for traction. Once the diffs started plowing, and the bumper and skid plate were pushing snow, forward motion would cease. We then had to break the snowpack with narrow, heavy shovels, picks, or axes.


We theorized that a lighter truck, like the 404 Swissies, could possibly drive over some of these layers and prepare the way for the heavier radio trucks. The idea worked as Tyson (with a winch) led the way into the first significant obstacle, a sharp turn with over 3 ft drifts. Progress was slow, but the Swiss mog was able to claw through the hard snow about an inch per tire revolution. The chains had to eat their way into the stuff, allowing slow but continuous progress. If forward progress stopped, the tires would continue digging downward and the truck would sink. Eventually, as the drift deepened, the truck was resting on the packed ice and the tires were no longer getting any traction.

Winch time (sure beats digging!). Tyson's winch cable was laid out to a good anchor, a heavy metal culvert, and the winch dragged the truck through the worse of the deep snow until the tires got traction again.

Following Tyson's tracks, the other three trucks made it through that corner with some difficulty, but without assist. We did notice at this time that the radio trucks dug even deeper than the Swiss trucks. In fact, coming back down later in the day my radio truck dug so much deeper at this spot that we almost got stuck on the high center ridge we had passed easily before.

. .

We continued on up the road, passing several stretches with deep snow, but none that required digging. Progress was slow as the chains ate their way through the snow and ice up to 2 ft deep.

Then we came to the first real drift. Snow had blown in from the north causing the south facing roadcut to almost completely fill up. The only way to continue would be to dig for hundreds of feet.

The smart thing to do would be turn around and go home. No one ever accused us of being smart. It was only about 10 AM and no one was willing to give up yet. We had the opportunity to try to clear this approximately 300 feet long blockage with slim hope of continuing very far beyond, but, maybe more importantly to us Moggers, we would find out what we and these machines could really do!

The amount of snow to clear was substantial. In many places on this 100 yard long drift, the snow was drifted in to completely fill the road cut, leaving a continuous slope from the mountain above to the mountain below. Cutting a channel just the width of the mogs, even leaving a final depth of maybe 2 ft on the road, would still require shoveling up to 5 ft thickness of laminated ice and snow on the upper side, and a couple of feet on the lower side. That technique would leave 2 ft of road edge plus a snow/ice barrier along the downhill side to provide safety for the trucks.

Our other serious concern was that the hard layers of ice were tilted at near the slope of the mountain. If a truck were on one of those layers, and the slab of ice broke loose, the truck would have no chance to stop. Trenching along the inside edge of the cut would have the truck resting on two different layers. That would also keep the truck tilted toward the mountain and help prevent slipping.

The tendency of the snow to lay in tilted layers is the very reason that snowmobiles and snow cats can't do this job. They could easily slide off the mountain.

Even as several people had already started the shoveling, a group decision was made to start shoveling! Someone was overheard to say "what a beautiful day to dig". We soon found out what the early miners went through. Heavy digging above 10,000 ft elevation was a lot of work!

Two stages of digging were required. The aluminum snow shovels could not penetrate the ice, so first the stuff had to be broken into chunks. Then the chunks could be picked up by hand, or shovel, and thrown off the mountain. The picks from the 'frontier' packages on the Swiss trucks worked well, as did a couple of narrow steel shovels.

Some of those ice chunks continued rolling down the mountain for up to 300 ft, showing just how steep the mountain was at this point. There were no trees to stop a truck. Noticing that situation, someone asked: "what happens if a Unimog rolls off the mountain?". The answer was: "then we know we didn't do it right". We were determined to do things right.

After we had dug maybe 50 ft of 'Unimog ditch' into the drift, Tyson decided to try driving that far. The width of the cut was adequate, and there was little tendency of the truck to dig toward the lower side of the cut. The method looked safe. Tyson did reach the differential-depth limit several times and the bottom of the trench had to be lowered some more (more digging). At this point we had only dug about a third of this drift so Tyson shut it down and we went back to work.

For 4 or more hours we shoveled and rested, and ate...then shoveled some more. Eventually that drift was busted, and the next one too. More winching was required toward the last of the drift, using a big rock as a winch anchor. Tyson made it through, and Rodger followed in his Swissie. Each truck was bottoming out on the differentials so Rodger got a tug from Tyson to get through.

Fred and I with our heavy radio trucks made the decision to stay back where we were and not try the drift. We knew our chained tires would just dig the tracks deeper, we'd high center, and we didn't have enough cable among us to reach the middle of the drift from either end. Not a nice prospect with just a few hours of light left and the other trucks trapped on the upper side.

About that time the word came back from the trucks up ahead that there was another big drift about half a mile up the road. The turnaround decision time of 2 PM was approaching so we knew this trip had achieved all it could do. We had had a good time, appreciated the Colorado high country scenery that few people get to enjoy in winter, and learning more about what our trucks could do.

Even though we had to retreat, the trucks' performance was still amazing. Dr. Stencel commented that Unimogs were still the most cost effective way of extending the season for observatory use.

. .

We all headed back down the mountain, unchained, and departed for lower, warmer country, and pizza, in Idaho Springs. The pizza and socializing was great! Thanks Dr. Bob!

Thanks again to the University for this third opportunity to test our trucks, and provide assistance to the Astronomy Dept at DU. Sorry we didn't make it, but there's always next time. The next time may be next fall, however, unless there is an unusual dry and warm period early in January.

Bob Ragain

Go back to the November 21st, 1999 RMM Outing, Mt Evans Expedition #2, Colorado trip report Go to the Web Site Map Go forward to the January 29th-30th, 2000 RMM Outing, Mt Herman Road, Rampart Range area trip report
Copyright © 2003 Last modified Saturday, February 05, 2005 02:12:02
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