Early risers in the north shore corridor witnessed the formation of waterspouts hovering over Lake Chapala on Thursday, July 25.
Photographs and videos were recorded from various points between San Antonio Tlayacapan and Jocotepec, shared on social media throughout the morning. A waterspout is a funnel cloud with an intense vortex that swirls over a body of water, usually associated with a cumulus cloud.
The Spanish terms that describe these weather phenomena are tromba marina (marine tornado) and culebra de agua (water snake), the latter being more commonly used in the local vernacular.
Tornadic waterspouts are ordinary tornadoes that form over land and then move out over the sea or a lake. Their formation depends on a mesocyclone — a rotating, low-pressure column two to ten kilometers wide — that develops inside a supercell, a particularly severe, organized, and long-lived type of thunderstorm. Because tornadoes generally need the stronger surface heating and sharper air-mass contrasts found over land, tornadic waterspouts are rare compared to the more common “fair-weather” waterspout. They can also be far more destructive, with wind speeds reaching up to 438 kilometers per hour.
Nonetheless, the milder type of waterspout may pose a serious risk to navigation. And in the case of Lake Chapala, culebras de agua that lift water from the lake and drops their contents on the neighboring mountain range when moving inland have been associated with flooding and debris slide incidents that have stricken north shore communities throughout history.
Experiences with tragic waterspout outcomes spawned the superstitious practice of yesteryear in which local inhabitants, often young boys, would raise a machete in the air and slash it over the face of the funnel cloud to break up the snake and make it dissipate before striking the mountains. Lengthy landslide scars appearing on hillsides are still commonly known as piquetes de culebra, or snake bites.
What seems unusual about last week’s waterspout sightings is their occurrence in the first weeks of the rainy season. The ominous funnel clouds most often crop up in August and September. The lakeshore region is more prone to natural disasters when mountainsides are fully saturated with rainwater and waterspouts unleash in combination with heavy storms.