Colli is that high hill located right behind the Omnilife Stadium, which on Sunday (October 30) will be the focus of much attention for the closure of the Pan American Games. The hill, of course is actually a volcanic plug created after the Primavera Caldera’s last explosion about 25,000 years ago. In the June 4, 2010 Reporter, I described our discovery of a steep path up the south side of Colli from the prolongation of Avenida Guadalupe. The trail we followed was hot and dusty, without a square centimeter of shade, but we found plenty of tall pines, brisk breezes and of course a great view, once we reached the top.
Recently I went to visit a friend working at a research institute located on the opposite (north) side of Colli, nestled right at its foot. The institute, called CINVESTAV (Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional) mainly carries out research in electrical engineering, electronics and computing. Our friend, Dr. Arturo Sanchez is working there to develop practical ways to turn farm byproducts into gasoline.
Naturally, I mentioned our hikes up the other side of Colli to Dr. Sanchez who told us there just happened to be a very beautiful (and conveniently shady) trail leading from his institute all the way to the very highest point atop Colli Volcano, “from which,” he added, “you can see Guadalajara in all its splendor and smog.” I suspect you could also see the whole show at the Omnilife Stadium as well, though I haven’t yet checked out that side of the hill.
Not long ago I talked Dr. Sanchez into leading a group of hikers up to the very highest point on top of Colli for a good look at the City of Roses. “And if we are lucky,” I added, “we may even find ourselves a fumarole,” referring to a rumor I heard years ago that there are vents emitting hot gases somewhere up on top of the ancient plug.
During the very first part of our walk, even before leaving CINVESTAV’s grounds, we found ourselves in the middle of a widespread obsidian deposit where we found quite a few partially worked pieces. I wonder whether local archeologists have registered this particular deposit. Obsidian fields seem to pop up everywhere we go west of Guadalajara.
For the most part, this trail is nicely shaded and scenic. From the top, you have a good view of the Bosque La Primavera and then you plunge into an oak forest occasionally broken by huge piles of jagged rhyolite boulders. These, says Canadian geologist Chris Lloyd, are the fragmented remains of Colli’s last spurts of lava, which oozed out of several easily identified volcanic domes that we passed.
Suddenly you step out of the forest into a big meadow of tall golden grass waving in the breeze. From here, it is less than half an hour’s walk to the very highest point on top of old Colli, at 1976 meters above sea level. As you approach this spot, a panoramic view of Guadalajara suddenly spreads out below you. I’m surprised some entrepreneur hasn’t put a hotel or restaurant up here.
While taking in the dramatic view, our geologist friend casually mentioned that the Caldera has a history of new eruptions every 25,000 years, “and it’s about due for another one right now.” Now you may be thinking, “I’m not sure I would enjoy my chile relleno while sitting on a volcanic plug that could blow any minute.” However, I suspect all the rest of Guadalajara would vanish only a split second later, so what’s the difference? As Tom Lehrer gruesomely put it in the 1960’s, “We will all go together when we go.”
The trail up to Colli’s peak from CINVESTAV is three kilometers long and is surely the most beautiful and pleasant of all the paths I’ve seen on this hill. In two hours, you can reach the peak at a leisurely pace, leaving you plenty of time to search for those now legendary volcanic vents … and, just in case you find one, remember not to get too close!
How to get there
Take Avenida Vallarta west to the Periférico and take the entrance ramp that will get you going south toward Colima. After driving only 2.3 kilometers, you will pass under a large pedestrian bridge with UVM (Universidad de la Valle de Mexico) written upon it. Take the very next right, a divided boulevard. Go straight. The road ends at a little roundabout. Circle around it and head back the way you came. The next thing you’ll see is the gate to CINVESTAV, whose buildings are orange and red, with Colli looming behind them. Because this institute is not open to the public, arrangements would have to be made for gaining access to the hiking trail. If you are interested in this, contact me at This email address is being protected from spambots. You need JavaScript enabled to view it.. But don’t wait too long: remember, the Caldera clock is ticking!