El Río Seco is a beautiful, ever-changing canyon that will please hikers of all abilities.
This “Dry River” is three kilometers long and runs directly southeast from the northern edge of the Primavera Forest.
The walls and floor of the canyon are literally reshaped after every storm, revealing fascinating new rock formations which often surprise and delight visitors who have hiked through the very same place just the week before.
The Río Seco is a perfect walk for families with small children. Because the first part of the canyon is particularly beautiful, even those who walk only ten minutes and then turn back will feel their short hike was well worth it.
The walls of this canyon often tower 50 meters above you and they have a story to tell. In fact, geologists from all over the world will come to Bosque la Primavera only to gaze upon sheer canyon walls like these, because they clearly tell the story of cataclysmic events which unfolded in this part of Mexico long, long ago.
That story is obvious to a geologist but it can also hold meaning for the rest of us. First, consider this: 95,000 years ago the area encompassed by what is now the Primavera Forest, exploded in a Yellowstone-style volcanic eruption, which threw 40 cubic kilometers of ash and rubble high into the air, leaving behind a huge hole or caldera, which then filled with water and became a lake for ten to 20,000 years.
According to geologist Barbara Dye, volcanoes eventually rose up in the lake and spewed out a sort of volcanic foam which hardened into pumice rock, so light it floated on the surface of the lake for a while, but eventually sank to the bottom.