Unimog Expedition in Mexico

Altar Dunes, Puerto Penasco and El Gulfo 

Trip Report:  November 1-8, 2002

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Conquering the Altar Desert in Style


Northwestern Sonora in Mexico is one of the largest remaining remote areas south of Canada.  This area is hard core desert, cruel in the summer and unforgiving of mistakes.  Four wheel drive clubs in the southwest have been making crossing of the Altar Dunes from either the Sonoita area or from San Luis del Colorado south of Yuma, AZ. for many years.  This area offers one of the last remaining true adventures within easy driving distance from the US.  I had done this trip in 2000 with the same crew, so we had good knowledge of the rigors that faced us.  Indeed, the Altar is a test of man and machine as well as your logistical planning skills. 

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The Trip

The planned trip involved getting three Unimogs across the Mexican border, to San Luis del Colorado, Sonora then east along Mexican Highway 2 (the main highway) toward a small "truck stop" called Cesar's.  Cesar's is about 17 miles east of San Luis.  From a small dirt road just before Cesar's, we would head south for the high dunes.  Unlike the last trip, we planned to traverse the entire Altar dune field.  This would require 3 full days of hard-core travel to the next semblance of civilization and would span over 200 miles of the dunes.  The general plan was to pick a point off the map and then use the GPS to help us navigate to the waypoint.  This point was arbitrarily selected by Dan and is shown in the GPS Waypoint table below.   From there, we were to head to Puerto Penasco (Rocky Point) in Sonora for supplies and then return via the beach and dunes to Cesar's and then to the boarder.

Once in Rocky Point, we would refuel, re-ice and buy camarones (shrimp), almejas (clams) and then find a suitable camping spot on the Sea of Cortez.   See the satellite photos and maps lower on this page.

Given the time requirements to make this long crossing, substantial pre-planning was required. To do such a trip required detailed knowledge of what conditions were expected as well as research on issues beyond just road conditions.  To prepare for this trip, we utilized experience gained from the previous trip, tide charts, satellite photos, Mexican maps as well as other intelligence gathered from the local four wheel clubs.  As we will see later, knowledge of the tides was of critical importance given that we intended to travel on the beach and could become trapped against the cliffs if the tide turned against us.

To insure the success of a major expedition in a foreign country, it is absolutely essential that the proper team of vehicles and operators was assembled.  Of  key importance was vehicle reliability.  The size of the Altar dunes basically precludes the ability to tow a truck as dead weight.  While theoretically possible, the time required to complete the winching make recovery a practical impossibility.  Therefore, special attention was given to mechanical preparations prior to the trip.  And, in general, this paid off in a relatively trouble-free trip, tire issues notwithstanding.

The Expedition Team

The away team for this expedition consisted 7 humans and 3 Unimogs:

From Left to right are: Bill Caid (San Diego), Scott Clements (Indiana), Kai Serrano (San Diego), Matt Oliphant (Los Angeles), Dan Johnson (Indiana) and Nancy Oliphant (San Diego).  Below, is Kathleen Jones (San Diego), the resident self-appointed "trail dominatrix".


All drivers had substantial experience in hard-core off-roading.  All had completed the Rubicon and all the hardest trails in Moab. Additionally, this group had previously successfully done the high dunes of the Altar Desert in 2000 and lived to tell about it.

The Equipment

The team had a trio of full sized diesel Unimogs at it's disposal.  These vehicles were trail proven in a number of situations and were sufficiently powerful to make it through the very soft sand of the Altar Desert.  The equipment list:
Bill Caid and Kathleen Jones from San Diego were in Caid's 1979 U1300L (435 single cab) with 1987 Yamaha Banshee ATV.
Dan Johnson and Scott Clements  from Indiana were in Dan's super clean, tricked out 1992 U1550L (435 single cab).
Kai Serrano, Matt and Nancy Oliphant from San Diego and LA respectively were in Kai's 1978 U900 (416 double cab).

A comparative shot of all three vehicles is below.


Photos of the individual rigs are below.  First, the 1300L with Kathleen doing a reasonable Vanna White impression.  For this trip, I purchased a used set of Goodyear 24x20 Terra Tires and custom rims to help negotiate the soft sand.  As a "side benefit" the tires increased the track width to about 9 feet, giving good stability on side hills.

Next is the 1550L with some magnetic flames for that extra speed.  Given that the 1550 has the OM366 motor, the flames were justified.  Dan is running the 22x20 Continental sand service tires on stock Unimog rims.  His rig, in addition to a spare fuel tank, also has central tire inflation which was as much of a hindrance as it was a help.

Kai's 416 cow mog was fully loaded with camping equipment and equipped with Continental 22x20 sand service tires.  These tires were purchased used and was the only set that did not give us problems.  Also, for we got to use the winch several times as both he and Dan got stuck in the mud near the water's edge.

 Geography of the Altar Desert

The area traversed is hard core desert; massive dunes that go for hundreds of miles.  This consists of alternating desert scrub (AKA "tundra") and big, razor-back dunes.  Some of the dunes are over 500 feet high and are composed of very soft sand the consistency of flour. Figure 1 shows a satellite photo of the general area.  Figure 2 below shows a zoom of the area of operations for this trip.  True north in these photos is about 30 degrees to the right of the left border.  See maps below for more accurate representation.

In Figure 1, San Diego bay is just below the top edge on the left.  The large lake is the Salton Sea.  Farmed areas are shown in red.  The road in Mexico that parallels the border can be seen.  Refer to the map below for reference.

Figure 1. Satellite Photo of Northern Baja and Northwest Sonora, Mexico.

In Figure 2, the large dunes are evident and can be seen as forming a set that roughly parallel the coast to the south.  The destination was El Gulfo de Santa Clara, and this is due east of the end of the largest "gray colored" island at the mouth of the Colorado River.

Figure 2.  Zoom Photograph of Area of Interest.

Trip Details

Maps of the Area

Two maps of the area are shown below in Figures 3 and 4.  Both are 1:250,000 topographic maps that were imaged with my digital camera and then cropped.  The main parallel lines are on 10 km increments.  Click on the map to get a full resolution view.  This is a 300kb file, so if you have a phone modem, this will take a while to load.

Figure 3.  Map of the Northern Portion of the Trip.

Figure 4. below shows the southern portion of the trip. Click on the map to get a full resolution view.  This is a 300kb file, so if you have a phone modem, this will take a while to load.  The parallel lines are 10km marks, so distances can be estimated from them.

Figure 4.  Map of the Southern Portion of the Trip.

On this trip, I never did get a good estimate of mileage.  When I looked at the odometer, it was on either day 2 or day 3.  When left the dunes, given that reading, we had traversed nearly 300 miles of territory.  Total fuel usage for my 1300 was about 130 gallons border to border.   I only took on fuel in Puerto Penasco as El Gulfo was out of diesel (again).

GPS Waypoints

For those readers that are technically minded, the table below contains the UTM coordinates of our camp sites.  The datum is NAD-27.  



East Coordinate

North Coordinate

Start at Cesar's 11 735656E 3586700N
Goal 12 239566E 3515816N
Camp 02-11-2002 11 736003E 3566682N
Camp 03-11-2002 11 756691E 3542520N
Camp 04-11-2002 12 216648E 3528128N
Camp 05-11-2002 12 249989E 3484091N
Camp 06-11-2002 12 249989E 3484091N
Camp 07-11-2002 11 727100E 3539822N
End 11 735656E 3586700N


Day by Day Details: descriptions and photos

Day 0: 01-11-2002 Getting to Yuma and the trail head

Day 1: 02-11-2002 Leaving for Sonora

Day 2:  03-11-2002 The Cross to Camp Sidewinder

Day 3: 04-11-2002 Camp Sidewinder to Camp Scorpion

Day 4: 05-11-2002 Beach Rescues and Other Follies

Day 5: 06-11-2002 Visit to Puerto Penasco

Day 6: 07-11-2002 Encounter in the High Dunes

Day 7: 08-11-2002 Return to the USA


Conclusion and Traveler's Tips

As expected, there were a number of Mexican road checkpoints.  One was manned by the Mexican Army regulars.  The others were manned by various departments within the Mexican law enforcement community.  There were no problems encountered and all the personnel were amiable.  However, it is a law within Mexico that all vehicles (particularly those owned by foreigners) have liability insurance for their automobiles.  This means that you will have to have valid registration and plates for your vehicle.  Additionally, there are frequently tourist visas that must be obtained at the border.  I say frequently as it seems to change like the tides.  (It was not required this trip, but was the last). These not only require check in, but surrender of the documents upon departure from the country. These visa cost 170 pesos (about $20).

El Gulfo is a very small town; this is primarily a fishing village, but does cater to tourists, particularly Gringos around Thanksgiving, Christmas and New Years.  There is a Pemex station, and it probably has gas.  I say probably, because in Mexico, if the fuel truck does not show up for what ever reason, then there will be no gas.   There is a store and ice is available along with plenty of fresh fish, shrimp, clams and sometimes other shellfish. Water is in short supply, but can be purchased at the town store. There are several RV parks in town and several "hotels".  The quotes are used here since one of the selling features of the hotel is that it has indoor plumbing.

The locals make their living fishing, and good seafood is available at all times.  The best restaurant in town is the El Delfin and has excellent food. 

Miscellaneous Information

Although our crossing was made in November, it was warm to  hot during the day.  Typically, the evenings can be cold, so come prepared.  Rain is not out of the question and indeed we did have light rain on two days.  Wind is highly likely, so protection from blowing sand, including goggles is a requirement.  And, should the wind come, having a fallback for cooking is a good idea.  High wind and blowing dust will put the chingas to any BBQ and will make a task as simple as boiling water a challenge.

Firearms are prohibited in Mexico.  Handguns, in particular, are frowned upon.  If you are caught with one in your possession, you will go directly to jail.  There is a very high likelihood that you will be unable to "buy" your way out of the situation no matter how much money you have with you, so this situation is better avoided.  While lack of a firearm in the wilderness will place you at somewhat of a disadvantage should trouble arise, the penalty for possession is so harsh that it is not worth the risk.  The proposed area of operations is known to be used by drug smugglers.  However, the open desert crossing is not the preferred route, so the chance of encountering anyone is nil.  But, the Mexican Army does patrol both the north end and the sea-side of the desert and if they stop you, they will most likely do a thorough search of the vehicle.  They pose no threat to honest Gringos that do not break the laws of their country. 

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