sailing stones on the racetrack (death valley)


Sailing Stones on the Racetrack dry lake in Death Valley (California)

Sailing stones are rocks that move in long tracks on the smooth and perfectly flat surface of a dry lake, without human or animal intervention.­ The rocks are most likely propelled by strong winds while entrapped in floating ice sheets (or icebergs), after winter rains flooded the dry lake and made the mud soft and slippery.­

This photo was processed in True Tone HDR and Tone Mapping from a single RAW exposure.­

cracked mud death valley desert dry lake dry mud mountains moving rocks racetrack playa sailing stones sliding rocks tracks
Racetrack Valley Rd, Death Valley National Park, Death Valley, CA, USA

Photos processed in True Tone HDR.­

Those are High Dynamic Range (HDR) photos processed to represent the scene as observed by the human eye, i.­e.­ without some of the surreal effects that can be obtained with "heavy" tone mapping of HDR images.­

See also related series: HDR Photography (High Dynamic Range).

I sometimes do HDR processing from a single RAW exposure, since my camera has about 6-stop dynamic range in RAW mode.­ This is the only possible way to do HDR when shooting a moving subject.­

For those wondering about the technical part, here is some information about my workflow for producing tone-mapped HDR images from a single RAW exposure:

- The RAW image is used to generate 3 images using exposure compensation with Photoshop using Adobe Camera Raw: -2EV, 0EV and +2EV.­ This allows to capture about the entire dynamic range stored in the RAW file.­ You could also use Lightroom to do that too, or any software than can process those RAW files.­ In my case, I need to first convert the RAW files into DNG format (using the standalone Adobe CameraRaw Converter) because the version of Camera Raw that I can use with my Photoshop is not compatible with the RAW format of my (recent) camera.­ But you don't need to go through the DNG step if you have the latest Adobe software.­

- The 3 images (-2EV, 0EV and +2EV) are then merged into one HDR image using Photomatix (you could also use Photoshop to do that).­ This is basically an automatic process with no parameters to adjust.­

- The HDR image is then processed with Tone Mapping to obtain a displayable image.­ I use Photomatix for the tone mapping.­ There are many knobs that can be adjusted, but in general, to get a True Tone realistic image, I use 25% to 50% intensity in the Tone Mapping dialog.­ I then save the resulting tone-mapped image in TIFF format.­

- If needed, I then correct Chromatic Aberrations using the free and automatic Photoshop plugin from Photoacute, which works very well most of the times.­

- I then use standard Photoshop layers to do the usual final adjustments (Level, Curve, Saturation, Color Balance).­

Photos taken in the Death Valley National Park.­

Related series:
- The Mysterious Sailing Stones of Death Valley
- Grotto Canyon (Death Valley)
- Fall Canyon (Death Valley)
- Mating California Toads (Darwin Falls, Death Valley)


And don't hesitate to drop me a word!

Photos of the "Sailing Stones" on the Racetrack dry lake in Death Valley (California)

The "Sailing Stones" are rocks that move in long tracks along the smooth and perfectly flat surface of a dry lake, without human or animal intervention.­

The best time to take photos of the sailing rocks and their tracks is just before sunset, or just after sunrise, when the light is grazing.­

Those rocks move several hundreds feet every couple of years, during winter, but no-one has ever observed them moving.­ It is likely that the weather is extremely cold, wet and windy when the stones move, and by this type of extreme weather, no-one really wants to be there!

The rocks are most likely propelled by strong winds while entrapped in floating ice sheets (or icebergs), after winter rains flooded the dry lake and made the mud soft and slippery.­

The natural process, as currently understood, involves:

1) heavy rain flooding the lake with a significant layer of water.­

2) rain is followed immediately by below freezing temperature causing the water on the lake to freeze, entrapping the rocks in ice sheets.­

3) more rain before the ice sheets melt, causing these ice sheets to float, The rocks are partially lifted by the icebergs that entrap them, reducing their apparent weight on the muddy bottom.­

4) strong winds breaking the floating ice sheets and pushing them around, causing the entrapped rocks to move and leave tracks on the muddy bottom.­

Because this combination of weather events is complex, it does not happen every winter.­

For more information about the Racetrack sailing stones, read:
- en.­wikipedia.­org/­wiki/­Sailing_­stones
- en.­wikipedia.­org/­wiki/­Racetrack_­Playa
- www.­smithsonianmag.­com/­travel/­how-do-death-valleys-sailin.­.­.­

Related series:
- Grotto Canyon (Death Valley)
- Death Valley