Before its dramatic collapse the San Rafael Falls were a breathtaking spectacle. Towering 131 meters high it was Ecuador’s tallest and most powerful waterfall. Located in the eastern Andean foothills about 170 kilometers east of Quito the San Rafael Falls were a magnet for tourists. Its beauty drew thousands of visitors annually. In 2019 approximately 30000 people marveled at its cascade.
Formed thousands of years ago the falls had a fascinating origin. Debris and lava flows from the nearby El Reventador volcano played a crucial role. Around 19000 years ago a massive debris flow from the volcano cascaded into the Coca River valley. This was followed by a volcanic eruption. A 100-meter-thick basaltic lava flow blocked the river. This created an incredibly erosion-resistant lava dam. The river’s water spilled over the top forming the waterfall.
Over time the plunge pool at the base expanded. A large overhanging precipice and cavern formed where the hard basalt rested atop loose material. The waterfall’s location remained relatively stable for millennia. The hard basalt protected the loose material below from erosion. This stability lasted until February 2 2020. That day a sinkhole above the falls collapsed. A large portion of the Coca River’s flow vanished into the sinkhole. The remaining loose material under the lava dam was quickly washed away. The result was a massive natural bridge. The waterfall as it was known disappeared.
The collapse had devastating consequences. It significantly altered the Coca River creating a deep new canyon upstream. Large volumes of sediment flowed downstream. Upstream erosion destroyed several bridges and oil pipelines. The Coca Codo Sinclair Dam built upstream in 2016 is now threatened. Some researchers believe the dam’s impact accelerated the collapse. This is due to the dam trapping sediment and increasing the river’s erosive power.
The San Rafael Falls a once majestic natural wonder left an indelible mark on Ecuador’s landscape and history. The site of the falls is a testament to the powerful forces of nature and the unpredictable nature of geological events. Though gone its legacy endures a reminder of both natural beauty and the delicate balance of ecosystems.