Entering a tunnel driving in the rain and coming out the other side on a sunny day, or the other way around, is an unusual experience. The most normal thing is that when we enter the car through those underground passages that in Spain add up to a total of 400 kilometers of road, we find ourselves with the same time that we left behind just a few moments before.
In this way, when the day is sunny, it is most likely that the atmosphere will remain that way once we have passed the tunnel. And if it rains, the rain will likely continue when you go outside again. Even in the longest tunnels, such as the Viella tunnel, which is 5,230 meters long, the transition from one end to the other does not usually offer significant variations from the moment one enters the road infrastructure until the moment it exits.
However, on the island of La Palma (Santa Cruz de Tenerife) there is a tunnel that has captured the attention of many users on social networks due to its uniqueness. It is on the LP-3 highway and crosses the ridge of the Cumbre Nueva, a volcanic-mountainous massif, to the Curva de los Andenes. This underpass is popularly known as the time tunnel because it is common for the climate to change completely once the 2,665 meters that separate one entrance from the other are exceeded.
This phenomenon has been captured in numerous videos published on social networks over the last few years. In the recordings you can see how drivers driving in the rain enter the tunnel with gray skies and persistent rain. But upon emerging on the other side, they are greeted by a completely different landscape: a sunny day, with clear skies and bright sunlight.
This surprising and almost magical transformation is due to the fact that the tunnel passes through a mountain system that acts as a climate barrier. This is what is known as the windward (wet, windy slope) and lee (drier, windless slope) phenomenon.
In the recordings that you can see in this article you can also see the evolution of the road and the interior of the tunnel over the years. This infrastructure dates back to 1970, the date on which the Cumbre highway (LP-3) was inaugurated. Until then, communication between the two slopes was carried out by the southern regional highway, crossing the municipality of Fuencaliente.
Since then, the road has been improving its safety and being partially remodeled with the creation of overtaking lanes for slow vehicles and improvement of intersections.
Regarding the tunnels that are part of this route, a series of significant renovations have been carried out. Lighting has been improved to ensure greater visibility inside the tunnels, walls have been reinforced and lined to increase traffic flow, and more effective drainage systems have been implemented to avoid flooding problems.
In addition, ventilation adjustments have been made to ensure optimal air circulation and more advanced emergency systems have been installed to respond quickly to any incident.