Can waterspouts cause destruction? – Meteorologist Robin Maharaj explains

By Michelle Nurse Last updated Aug 21, 2018

(Trinidad Express) 20 August, 2018 – I have had several inquiries from people in Trinidad regarding waterspouts in general, and particularly about one such phenomenon seen in the Gulf of Paria just after mid-afternoon on August 10, 2018.

I received video as well as pictures of this event. In appreciating my response a few persons suggested that maybe, readers could benefit from the explanation, brought to the layman level, of the phenomenon. It is in that regard that I write, since I am certain you received news and queries about the same event.

Over the many decades during which worked as a meteorologist at the Piarco Weather Office, I saw with my own eyes several dozen waterspouts altogether. In some cases, I was actually looking out for them as I had forecast favorable conditions for formation. But several others just appeared when I was out on fun and games, “liming” or at the beaches. A great variety of size and intensity occur off the North Coast, particularly off Macqueripe and Cyril’s Bay, as well as in the Gulf of Paria (where they are ubiquitous) and even off Cedros and Moruga in the Columbus Channel.

The waterspout is a rotating column (vortex) formed over bodies of water when there exist specific atmospheric conditions, including a near a calm, hot day. For Trinidad, another requirement is a clear morning and weak easterly winds. And it is primarily a feature of the rainy season, occurring during breaks from the rains. When the easterlies weaken between long rainy spells, hot and calm days usually dominate. Shallow water is favorable as it warms easily and provides a starter mechanism for waterspout formation. The Gulf of Paria is estimated at only 25 meters in maximum depth.

It is a wrong impression that waterspouts start from the surface of water. In fact, they start in the air and then connect to the water surface. Given the conditions mentioned above, vigorous up-drafting air currents form, generating tall cumulus clouds that are not moving around fast. Small scale rotations in the cloud build downwards to the water below. Eventually, coupling occurs as the heated ocean surface provides a ready and waiting support, and even probably, additional updrafts that begin to rotate in unison with the cloud’s downward induced spiral. That produces what looks like a water-surface-sweeping upward motion concentrated and directed up to the cloud base. My observation of Trinidad waterspouts is that they form attached to the dark bases of deep cumulus clouds that extend from a base around 1,000 feet, vertically into the atmosphere to at least 15-20,000 feet. These are called cumulus congestus clouds. Occasionally the clouds could be way taller (eventually becoming a cumulonimbus – thunderstorm cloud, extending to above 40,000 feet).