Mid-February 2023

Introduction

The normally pristine beaches of Old San Juan and Condado are covered with deposits of brown algae. Crews clean the stuff from the main beaches but one can still see piles of brown algae along the seconday areas.

The first two images are from Parc Escambron, on Isletta de San Juan. The third is from Condado, in front of the Hotel Tryst. I suspect the Condado beaches are raked and cleaned more frequently than the beaches at Parc Escambron.

Source of the Brown Algae?

So where did the brown algae come from? I suspect most people assume it is from near shore, washed up by the surf driven by the seasonal trade winds. I prefer a more convoluted explanation.

There was an unusually strong storm in the tropical Atlantic in early December. In fact, some forecasters thought it might develop into a hurricane. While Atlantic tropical storms in December are not all that rare, a December hurricane would have been truly unusual.

Here is a visible satellite image of Invest 99L, obtained at 10:30 AM, December 6, 2022. As noted above, forecasters thought the disturbance might develop into a tropical storm or even a hurricane.

In the event, Invest 99L stayed a strong but not tropical storm. But the strong low pressure system affected the winds in San Juan. Most of the time, during the winter months, the trade winds are from the east or east north east. However, the counterclockwise flow around the low pressure system generated strong winds from the north that lasted for about a week.

The next several images are from December 9, 2022. I went with friends to Pinones, a beach and restaurant area just east of San Juan. Here are some pictures of the surf that day.

So what does high surf in December have to do with brown algae in February?

The December storm developed near and passed over the Sargasso Sea, an area rich in algae. It is in a relatively quiet part of the Atlantic, between the easterly trade winds to the south and the westerlies to the north. It is a rich breeding for, among other species, European and American eels.

I suspect the December storm dislodged a good bit of brown algae, only now making its way to San Juan’s beaches.

That’s my story and I’m sticking to it.

I’ve written about brown algae before. Click here to see that post. And, by the way, I’m still looking for investors.

Notes and Sources

Except for the satellite image, the images are mine, captured by a digital camera and edited with Adobe Lightroom and/or Photoshop.

The satellite image of Invest 99L is from the excellent Eye on the Storm blog, written by Bob Henson and Jeff Masters. Click here to see their post about the December 2022 storm.