The primary purpose of pharos is to provide a guiding light to boats lost at sea. They offer a visual boundary which shows the captains of these boats and ships where the sea ends and the land begins. However, the weather on the coastline is notoriously unpredictable, and it is not always possible to see the light from the beacons.
When it is dark, and environmental conditions like fog or thick rain make it difficult to see your surroundings, it is vitally important that these towers are able to be identified. There are a variety of strategies that are used, to ensure that the beacon can be seen at all times. One of the most important aspects is the strength of the lamp being used. Most lenses will have an incredibly high percentage that they are able to reflect. This means that their light will be able to be seen through some extreme conditions. These lights will also flash in these kinds of situations to help them to be identified more easily.
In some instances, the weather can become so treacherous that not even the most reliable light will be able to penetrate it. In these cases, the beacon will use sound to inform everyone around them where they are. All towers are equipped with a foghorn for times of poor weather. The foghorn emits a loud, low pitched sound which can be heard over great distances. Initially, these horns had to be operated manually, but new lighthouses contain a sensor that can detect moisture in the air. When this apparatus detects water in the air, the foghorn will be activated automatically.
Another strategy employed by the designers of these towers to improve the visibility of these beacons is the decoration. A tower will usually be decorated in a style that makes it easy to spot in its surroundings. Lighthouses which are built in darker areas will be painted a solid white colour. This will help them stand out against dark environments such as forests or fields. Towers that are built in the regions that are prone to fog, or are situated against lightly coloured mountains, will be painted white with red stripes. The stripes make it easy to see these towers when you are unable to see anything else. It is vital that beacons are visible, even if the environment makes it impossible to see what is right in front of you.