How should you know if its safe to go?
How to Read a Beach
When approaching a beach, the most important thing is to remain calm and observe before entering.
There’s always something to learn about how the weather will change, the direction of the tide (if it is moving), and, above all, how the waves are breaking along the coast and how the excess water flows back out to sea in rip currents.
Whenever I arrive at a new location, I always feel a sensation in my stomach—a mix of excitement and nervousness. This is completely normal, and even after many years, I still experience the same feeling.
Here, I’ll outline step-by-step how to analyse coastal or beach waters effectively.
What Causes Disturbance in the Sea or Watercourses
The Basics – Using Weather Apps and Forecast Websites
Checking the Weather
I like to cross-reference multiple websites and then verify their data on location. For example, these days, we have tools like Windguru, Windy, Surfline (formerly Magic Seaweed), and many others—some great, others less reliable.
The trick is to cross-check basic information such as wave height (usually in metres or feet) with wave period (time in seconds). For instance:
- Wave height: Taller waves make swimming less comfortable and reduce visibility in the water, creating the sensation of being surrounded by small "water hills" that obscure views of the shore, direction, or your companions/boats.
- Wave period: Indicates the amount of water moving at any given moment, also known as "groundswell" (waves generated by distant winds). If there’s local wind, it results in "wind swell"—a nuisance for swimming!
When I want to enjoy a smooth swim full of “flow,” too much wave activity can make it difficult.
How to Read a Weather Map
It’s essential to remember that some apps (like Windguru) don’t always account for the coastline or land formations, providing raw data that must be adapted to the specific location. Additionally, you must identify if there’s secondary swell—this occurs when waves bend around continental or island masses, creating unexpected interference. Secondary swell can also affect seemingly protected bay areas, posing potential safety issues or disrupting initial plans.
When paying close attention, you’ll find plenty of information: wind direction, wave direction, estimated temperatures, wave period, and wave height. Don’t forget tides, as these play a crucial role if the swimming area is affected by tidal currents—a topic I’ll cover in another article.
Period
The wave period reflects the movement of water masses back and forth. For swimmers, shorter periods are better. On mainland Portugal, a period below 10 seconds is ideal if the wave height isn’t too large. In the Azores or Madeira, a period of 12 seconds is still manageable—but bear in mind that island conditions involve additional factors.
Wave Height
This is straightforward: wave height is measured from behind the wave in the Hawaiian style. What you see from the front is roughly double the height indicated on apps or weather services. For example, on the Algarve’s south coast, waves over 0.5 metres might challenge most swimmers when entering or exiting the water. However, on the west coast, conditions may differ—so, what now?
Coastal Factors and Swell Direction
Here’s where the seabed and coastline come into play. For example, if the wave direction is from the north but the coast also faces north, the waves are likely much smaller than forecasted for that specific location. In such cases, it’s crucial to observe for secondary swell, which Windguru doesn’t immediately display as it uses a mathematical prediction model without factoring in landforms.
Coming Up Next
In the next edition, I’ll cover reading currents.
.jpg)
Comentários
Enviar um comentário