Hummanaya which gets its name based on the "huu" sound it makes as pressurised air flows through its airways and chambers, is believed to be the second largest blowhole in the world, constantly putting out sprays of water up to 25-30m (82-98ft) and even over 100ft every so often. It also happens to be the only known blowhole in the island and is situated in the fishing village of Kudawellaalong the southern coast of Sri Lanka which is 5km to the west of Dikwella and 12 km to the east of Tangalle.
Hummanaya is a natural blowhole. The simple mechanism of a blowhole is as follows: There is a hollow cavern low down which fills with pressurised water as the tide comes in with force and the exit route for the pressurised water is via an upward shaft along which the water jets up at high speed and spouts out putting on a fantastic display of aquatic plumage. Some of these blowholes such as Hummanaya also make an interesting array of sounds from deep rumblings to high pitched whistles as air flows through their caverns and chambers.
As you walk up to the location you will pass by many sheds and shanty houses as well as vendors selling various wares from cheap sunglasses and hats to toys and others selling delicious snacks from batter fried sea food to baked items and drinks. There are steps along the way so access for those with special needs will be a challenge albeit possible.
Once you reach the spot you will begin to hear the deep rumblings and whistles as air flows through the passageways of the blowhole. You will see a rock formation cleft in two and every 10-15 minutes with a loud sound and a massive gush, a feathery spout of water will erupt high into the air sometimes easily in excess of a 100ft (31m). It is truly a sight to behold. Do not miss it if you are visiting the southern coast of Sri Lanka or travelling past.