Lake Retba in 3D: The Pink Salt Lake Beside the Atlantic

A salt lake outside Dakar that turns pink in the dry season, worked by hand and held off the Atlantic by a strip of sand. Here is how to explore Lac Rose in 3D with live Street View.

Lac Rose — Lake Retba on most maps — lies at the neck of the Cap-Vert peninsula northeast of Dakar, separated from the Atlantic by a narrow belt of dunes. It is shallow, extremely salty, and in the right conditions the surface turns pink: a milky rose in flat light, closer to red near the banks where the brine is thickest. Men work it all day, standing chest-deep, breaking salt from the bed with poles and loading it into wooden pirogues.

The honest problem is that the colour is not guaranteed. It comes from a salt-loving alga that reddens under strong sun in very concentrated water, so it shows best in the dry season and fades whenever fresh water dilutes the lake. Heavy flooding in recent years pushed a great deal of fresh water in, thinned the brine and drained much of the pink away for an extended stretch. Recovery has been gradual, so anyone travelling for the colour should check recent reports rather than trusting photographs that circulate online.

That is exactly the kind of place worth understanding before you commit to the drive out from the city. You can explore Lake Retba today in 3D, with live Street View on the roads around it, from your phone.

What makes Lake Retba special

The pink comes from Dunaliella salina, a microscopic alga that thrives where almost nothing else can. In water this saline and under this much sun it produces a red carotenoid pigment as protection, and enough of them together tint the whole lake. The stronger the brine and the harder the light, the deeper the shade, which is why the same water can look grey at dawn and rose at noon.

The salinity is remarkable, high enough in places to be spoken of alongside the Dead Sea, and high enough that a swimmer floats without effort. The lake was once open to the ocean and was closed off by shifting sand. What is left is a shallow basin behind a dune barrier, evaporating steadily under a hot, dry wind.

The salt is a working industry, not a display. Harvesters coat their skin with shea butter against the corrosive water, break the crust from the lakebed by hand, fill their boats, and carry the load ashore to the white mounds that line the bank. Much of it ends up preserving fish along the West African coast. For years the lake was also the finish line of the Dakar Rally, before that race left the continent.

How to explore Lake Retba in 3D

MAPAS renders terrain and imagery in real three dimensions, the only way to grasp how close this lake sits to the ocean and how thin the barrier between them is.

For a first run, try this order:

1. Search for Lac Rose, Senegal and switch to 3D so the dunes and the lake basin separate out of the flat map.
2. Tilt until you are looking from the lake towards the Atlantic, and see how little sand stands between the two.
3. Fly slowly along the shore where the salt mounds sit in a line above the water and the pirogues are drawn up.
4. Drop into live Street View on the approach roads from Dakar and around the lake to see the village, the sand tracks and the working banks at eye level.
5. Trace the route over the dune belt to the ocean beach, then follow the Grande Côte as it runs north.
6. Save the shoreline access you want and use GPS navigation on the day, since the tracks are easy to confuse.

Beyond Lac Rose

• Dakar — the markets, the music and the Atlantic corniche, an hour or so away depending on traffic.
• Île de Gorée — the island off Dakar, a UNESCO site and a memorial to the Atlantic slave trade.
• Ngor and Les Almadies — the westernmost point of continental Africa, with surf and a short boat hop to Ngor island.
• The Grande Côte — the vast open Atlantic beach running north from the dunes towards Saint-Louis.
• The Niayes — the market gardens in the damp hollows behind the dunes that supply much of Dakar's produce.

Season, light and why the pink appears

A photograph freezes one hour of one day, and at Lac Rose that is misleading. The colour depends on three things at once: how concentrated the water is, how high the sun sits, and how much wind is stirring the surface. The dry months, running roughly from late autumn to early summer, concentrate the brine and give the most reliable colour. The rains that follow dilute it, and after an exceptional wet season the pink can be absent for a long time.

What the 3D view adds is the geography behind all of it. You can see the lake for what it is — a closed remnant of a lagoon, held off the ocean by a dune ridge, shallow enough that a hot wind can take serious depth off it in a single season. Once that shape is clear, both the salinity and the fragility make sense.

Before you go

Travel in the dry season if the colour is the point. Midday, with the sun high and the wind low, gives the strongest tone, while overcast skies flatten it completely. The drive from Dakar is short in distance and unpredictable in time.

The water is harsh. Keep it out of your eyes, do not go in with open cuts, limit how long you stay and rinse afterwards. Give the working crews room rather than wading through them, and buy any salt you take home from the people who cut it.

Common questions

Is Lake Retba always pink?

No. The colour depends on salinity and sunlight, so it is strongest in the dry season and weakest after heavy rain. Flooding in recent years diluted the lake enough that the pink largely disappeared for a time, and it has returned only gradually.

Can you swim in it?

You can float in it easily, and many visitors do, but the salinity is extreme. Keep it brief, keep it away from your eyes, avoid it entirely with broken skin, and wash properly afterwards.

Is MAPAS free to use?

Yes. It is free on the App Store, needs no sign-up before you start exploring, and works on iPhone and iPad.

Lac Rose is a working lake before it is a spectacle, and that is most of what makes it worth the journey. The colour is the reason people come, but the labour is what stays with them.

Open MAPAS, tilt the dunes until the lake and the ocean sit side by side, and see for yourself how narrow that strip of sand really is.