Swimming in the boiling lake when it goes cold is not a good idea, no matter how enticing or gratifying it may seem.
Dominica's Boiling Lake is situated in the Morne Trois Pitons National Park, Dominica's World Heritage site. It is a flooded fumarole 6.5 miles (10.5 km) east of Roseau, Dominica. It is filled with bubbling greyish-blue water that is usually enveloped in a cloud of vapour. The lake is approximately 200 feet (61 m) to 250 feet (76 m) across.
Periodically, there have been fluctuations in the level and activity of the lake. In the 1870s it was deep; after a phreatic eruption nearby in 1880, the lake disappeared and formed a fountain of hot water and steam. Another phreatic eruption lowered the lake level by some 33 feet (10 m) from December 2004 to April 2005; later the lake level rose again, refilling the lake in just one day. The rapid draining and refilling of the lake implies that it is suspended above the local water table. A continuous flux of steam or gas generated by an underlying magmatic intrusion drives water up into the lake. A disturbance to the supply of gas can cause the lake to drain through the porous connection that normally allows steam to rise and heat the lake.
The lake rests at the bottom of a large sinkhole-like basin. More accurately, it is a flooded fumarole, an opening, crack or hole, in the Earth's crust, generally located within the vicinity of a volcano, which emits steam and gases escaping from molten lava below. Currently, the lake is viewable from a broad, cliff-top ledge about 100 feet (30 m) directly above its shore. High rock walls surround and create the basin. (Wikipedia)
On November 8, 2016, it was reported by tour guides that the "boiling" lake was no longer boiling and that the water level had dropped considerably, to being "almost dry". Over the past few days photos have been surfacing on social media of visitors swimming in the now cool boiling lake.
Throughout history, the Boiling Lake has gone through several phases of cooling, drying up and boiling. Unfortunately no one has witnessed the changes when they are occurring. When the lake goes from cool to boil, does it do so gradually or violently? Is there a sudden flash? Is there a sudden release of toxic gases? No one knows.
Swimming in the boiling lake, no matter how enticing or gratifying it may feel, is an extremely risky venture. It may be wise for the authorities to consider advising tour guides and visitors against participating in or encouraging such activity or even remaining by the lake for extended periods when it is in such conditions. Please remember, or be informed, that two persons lost their lives on the shore of Boiling Lake in December 1901, from strong gas emissions from the lake.