Earth Matters

April Puzzler

April 18th, 2023 by Lindsey Doermann
april puzzler image

Update on May 2, 2023: This puzzler image is a false-color view of seasonal flooding of Australia’s Diamantina River in April 2023. Congratulations to Steve Hawkins for being the first reader to correctly identify the image and to David Smith for finding its exact location. Read more about the location in our Image of the Day story.

Every month on Earth Matters, we offer a puzzling satellite image. The April 2023 puzzler is shown above. Your challenge is to use the comments section to tell us where it is, what we are looking at, and why it is interesting. 

How to answer. You can use a few words or several paragraphs. You might simply tell us the location, or you can dig deeper and offer details about what satellite and instrument produced the image, what spectral bands were used to create it, or what is compelling about some obscure feature. If you think something is interesting or noteworthy, tell us about it.

The prize. We cannot offer prize money or a trip on the International Space Station, but we can promise you credit and glory. Well, maybe just credit. Within a week after a puzzler image appears on this blog, we will post an annotated and captioned version as our Image of the Day. After we post the answer, we will acknowledge the first person to correctly identify the image at the bottom of this blog post. We also may recognize readers who offer the most interesting tidbits of information. Please include your preferred name or alias with your comment. If you work for or attend an institution that you would like to recognize, please mention that as well.

Recent winners. If you have won the puzzler in the past few months, or if you work in geospatial imaging, please hold your answer for at least a day to give less experienced readers a chance.

Releasing Comments. Savvy readers have solved some puzzlers after a few minutes. To give more people a chance, we may wait 24 to 48 hours before posting comments. Good luck!

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27 Responses to “April Puzzler”

  1. Mark Kevin Borucki says:

    Mouth/delta of the Colorado River.

    • William Hamilton says:

      How is that, MK Boruki? The Colorado runs dry long before it reaches where it *used* to have a mouth to the Sea of Cortez. Now that area is just a long-dry riverbed.

  2. Junia d'Affonseca says:

    Fingers lakes
    Or lençóis maranhenses

  3. John Amos says:

    I think this is the inland delta of the Niger River in Mali. Wonderful interplay of linear sand dunes and interdunal wetlands. And the subject of one of my all-time favorite, beautiful satellite images.

  4. Rafael Martinez-Gallo Vijande says:

    Niger inland delta

  5. Jim Green says:

    Lake(s) in California refilling due to recent heavy rains.

  6. Bill komendat says:

    Flooding in death Valley

  7. Matthew Burtch says:

    Appears to be a segment of the Amazon river’s delta in Brazil.

  8. Danny says:

    Okavango Delta. and differing color bands may be plant density, or water depth ?

  9. Alex von Hildebrand says:

    Okawango delta with beautiful deltas created by more or less deep waters.

  10. Nerissa-Cesarina Urbani says:

    Wetlands of Adair Bay

  11. Marco Bertazzoni says:


  12. Duca Ursula says:

    Mouths of Rivers

  13. Ian Cathcart says:

    Okavango delta (Botswana) in annual flood.

  14. Nancy Alicia Morales says:

    Río Grande, Tierra del Fuego, Argentina.

  15. Hollis Hoier says:

    Iceland, SE coast

  16. Steve Hawkins says:

    Looks like somewhere in or around Australia’s Simpson Desert, which, I think you posted a while back had some pretty rare rainfall events lately. I don’t see anywhere with quite the same colours, but the terraine is pretty distinctive.

  17. C.L.Makowiecki says:

    A massive kelp bloom some 5,000 miles across is moving across the Atlantic and could head for Florida’s Gulf of Mexico coast.
    The sargassum mass is visible from space and could be one of the largest detected in history.
    Red tide and blue algae come from different microorganisms. The red tide is caused by the species Karenia brevis, while a report issued to Manatee County commissioners recently identified the cyanobacterium Lyngbya as the cause of the local blue-green algae outbreak.

  18. Kaveh RADFAR says:

    This is a sattelite image of a desert in thé south east if Iran “kavir lut” which is normally dry. But in 2021 there was a rain and inondation thare which changed thé surface a lot.
    Thanks for the photo
    Kaveh RADFAR

  19. Ivan Kordač says:

    Desert flood somewhere maybe Namibia south from Luderitz (?)

  20. Arif Khan says:

    Parque Nacional dos Lençóis Maranhenses In Brazil

  21. Bett says:

    A satellite image of a region in North America. It is a river delta with various channels and a small lake, surrounded by wetlands and vegetation. It provides ecological value and for protecting against flooding.

  22. David Smith says:

    I’d guess an endorheic basin with a lot of dune action during a flood event. Probably either the Sahara or maybe central Australia. Looks like Landsat, probably using one of the SWIR bands, 6 or 7 on Landsat 8/9.

    • David Smith says:

      Okay yup, found it. Got curious and looked in the Sahara and in Australia, and spotted some north-northwest/south-southeast trending features in the Simpson desert, and actually found the exact features from the image in southwest Queensland, maybe 120km or so ENE of the little town of Birdsville. Definitely a flood event, almost certainly captured by Landsat or a similar sensor, and if Landsat it’s probably using Red and Green values from Bands 4 and 3 respectively, and then either Band 6 or 7 for Blue.

  23. Çimengül says:


  24. Ferne says:

    Is it part of the Ganges delta?

  25. Ivan Kordač says:

    I founded second idea

    west of Cairo desert dunes have the same orientations… Ivan