Martian avalanche crashes the party

By Phil Plait | April 8, 2010 5:30 am

Let me know if you get tired of these… no, wait. Don’t let me know. These pictures from the orbiting HiRISE camera never get old because they’re frakking amazing! Here is another awesome avalanche caught in the act… on Mars!

hirise_avalanche_april2010

Holy Haleakala! Coooool. Click the pic to nobly embiggen. And oh yes, you want to embiggen this one.

This may be my favorite Red Planet avalanche of them all. On the left you can see the surface of Mars: that’s frozen carbon dioxide — dry ice — covering the ground. The red brick-like pattern to the right of the ice is actually the face of a scarp, a steep cliff. We’re looking almost straight down on it, so it’s foreshortened, but don’t let that fool you; it’s 700 meters (2000 feet) high! On the right is the greyish floor, dusty basaltic rock. You can see sand dunes rippling across it, as well as a few boulders here and there.

But right there is the plume of a large avalanche, the cloud still rising above the floor! Clearly this was caught within seconds of the landslide hitting the floor of the scarp. The shadow of the plume is clear and obvious below and to the left. That’s particularly cool because knowing the Sun angle in the image means the plume height can be determined. They generally rise to 50 or more meters.

It’s spring in the northern hemisphere of Mars, and the warming temperatures are sublimating the dry ice. This may be causing the slides; the CO2 gets in the cracks of the rocks and dust, and when it goes away the loose debris can be free to fall. The folks at HiRISE have been targeting scarps like this one just in case they can catch avalanches like this.

I like this avalanche shot in particular because you can really see the contrast between the layer of ice, the scarp wall, and the floor. It makes for a wonderfully complete scene, and for some reason reminds me of Earth… maybe it’s because I live in Boulder, and I’m used to seeing ice covered red rocks with lots of interesting geological bits around. I’m not sure. But like all the other avalanche shots, it reminds me that Mars is a planet, a world, a location, an actual place. It may lack the dynamic and diverse weather we get here on Earth, but there’s still plenty going on at that little ball.


Related posts:

Another Awesome Martian Avalanche

Martian Avalanche Caught in the Act

Another Dose of Martian Awesome

Image credit: NASA/JPL/University of Arizona

CATEGORIZED UNDER: Cool stuff, Pretty pictures
MORE ABOUT: avalanche, HiRISE, Mars

Comments (55)

  1. Mike

    My new background!

  2. Mchl

    Wait! Isn’t that a T-Rex fossil on cliff face? Near the bottom?

  3. Any idea what that blue-green stuff is in the upper right corner? Reminds me of oxidized copper.

  4. Zucchi

    My gosh, that would be a great picture even if it were terrestrial! Looking up at the red dot of Mars, knowing it’s a hundred million miles away, and that we’ve got robots there sending back pictures — just fantastic.

  5. bac

    Great capture. Hopefully there are many more to come. I wonder what the photos would be like for the moon Io.

  6. 3. Tree lobsters

    The camera on HiRISE only has two visible-light colour sensors, red and blue-green, so a lot of the pictures returned show strange ‘blueish’ features which aren’t necessarily blue to human eyes.

  7. chimangolatino

    @Tree Lobsters : i think it may be a previous slide.

  8. Yes, this is mind-blowing. But 90% of great photography is just sheer luck (right place, right time)
    I jest.

    Amazing photo, thanks.

  9. Sman

    Nice! The obliqueness of the joint set appears as if it converges the deeper it gets. If so, wouldn’t that indicate propagation resulting from a decrease in lateral pressures… as the face of the scarp weathers away? Or, is there a large impact in the area?

  10. Wow!

    How much I would love to have an anaglyph for this image!

  11. @Mchl

    Wait! Isn’t that a T-Rex fossil on cliff face? Near the bottom?

    No, but it does look like the long-sought-for crocoduck fossil!

  12. Thorne

    Following the brighter line of the ice at the edge of the cliff from bottom to top, you can see from about the middle of the picture on up a darker, gray patch to the right of that white line. Could this be the newly exposed cliff face? If so, then that dark area shows how deep the dry ice has penetrated into the rock. I would imagine that, in a few days, this gray area will have disappeared, taking on the reddish color of the exposed face.

    But I have to wonder: what would cause these avalanches? Unlike water ice, CO2 ice doesn’t expand as it freezes, so I wouldn’t expect the constant cycle of freezing and thawing to actually weaken the rocks.

  13. threeoutside

    What’s the whitish smear that looks like it’s at the base of the cliff right where the avalanche fell from? It’s cool – looks like an eerie reflection, but I’m thinking it’s some of that frost that fell when the avalanche occurred? Anyone know?

  14. Pi-needles

    @12. Thorne asking:

    I have to wonder: what would cause these avalanches? Unlike water ice, CO2 ice doesn’t expand as it freezes, so I wouldn’t expect the constant cycle of freezing and thawing to actually weaken the rocks.

    Sublimation destabilising the dry ice I’d expect. Although I could be wrong.

    Indeed, that’s what the BA seems to be saying if you read the whole thing too :

    “It’s spring in the northern hemisphere of Mars, and the warming temperatures are sublimating the dry ice. This may be causing the slides; the CO2 gets in the cracks of the rocks and dust, and when it goes away the loose debris can be free to fall.”

    Well that or someone is down there yodelling too loudly! ;-)

  15. Darrell E

    Love this stuff. I think this is my favorite martian landslide pic as well, so far. Just makes me want to go there and poke around in person.

    One little general criticism. Though I rarely comment I have been a regular reader for years. In that time I have noticed that you are very loose with numbers. I understand that astronomers are often loose with numbers because there are often large uncertainties in the values that they deal with, and because they often deal with very large values. But you seem to aggresively adhere to this stereotype, even when converting a small metric value to British Imperial. Why not be a little more accurate and say “700 meters (about 2300 feet)”? In this context 300 feet is significant.

  16. I never get tired of pictures of Mars. When I first saw the pictures from Mariner 4, I never dreamed we would see things like this. Please keep posting them.

    It would be interesting if we could ever get a rover (or a geologist) up close to an area like this and get a good view of Mar’s geological history.

  17. LcNessie

    @ 5. Syrtis

    “red and blue-green”

    As in anaglyph stereoscopy? That *would* be cool… :P

    In another note, if there will ever be a mars-colony or other form of human habitat, I guess this demonstrates that we should be careful where we park our living-quarters…

    On second thought, I guess that goes for any planet…

  18. rob

    @Darrell E:

    an astrophysicist prof i had used to say “eh, whats a factor of ten amongst friends?”

    p.s. last night the cloud cover cleared enough so i was able to see venus and mercury. very cool.

  19. Obviously the exhaust from a Martian rocket. Calling Carl Phillips….

    @ Rob #18:

    p.s. Mercury, Venus, Mars, all in one (wide angle) eyeful! Beautious!

  20. JohnW

    I think I see a good 5.6 pitch just to the left of that patch of ice at the bottom…

  21. squirrelelite

    Here’s another cool picture from the University of Arizona astronomy department.

    It shows a 13 billion year old black hole. It is not surrounded by a dust cloud as most black holes are.

    As the Arizona Star article mentions:

    Until now, all black holes studied were surrounded by thick rings of dust produced by the debris of stars in the galaxy.

    But these two distant black holes lacked the surrounding debris, suggesting that heavy elements like oxygen, iron and silicon had not yet developed in the young galaxy.

    “That tells you that this black hole is in an environment that has not had a lot of things going on,” Fan said.

    While the astronomers don’t yet know all of the implications of these dust-free black holes, they hope to gain more information in coming years.

    “It’s a very encouraging sign that we’re on to something, but it leaves us with a puzzle,” Fan said. “We still have to solve what exactly is going on.”

    http://azstarnet.com/news/local/article_f6b3712e-0c1c-551e-91ef-a43efb195c63.html

  22. The “steps” of rock along the bottom of the scarp are interesting.

  23. ppb

    Todd W. @ 13

    The long-sought-for crocoduck fossil has been found – on Earth!

    http://www.abc.net.au/news/stories/2009/11/20/2748549.htm?section=justin

  24. Thorne

    @ #16: Pi-needles quoting BA:
    “the CO2 gets in the cracks of the rocks and dust, and when it goes away the loose debris can be free to fall.”

    Yeah, I caught that, too. But I wonder where the loose debris comes from in the first place. On Earth it’s caused by water seeping into cracks in the rocks, then splitting them when it freezes. This wouldn’t appear to be the mechanism here. I would expect any loose debris would have flaked off the cliff face a long time ago. So what could be breaking down the rock?

  25. That really is a cool shot. I’d like to see the same shot (with or without avalanche – doesn’t matter) with whatever camera we would have used before the HiRISE. I’d just like to have a visual idea of how much the resolution has improved.

    “Clearly this was caught within seconds of the landslide hitting the floor of the scarp.”

    I would think that plume would stay around for much longer than “seconds”. Dust floats around forever here on Earth and if I remember correctly, Mars has barely over third of our gravity.

  26. @25: “I would expect any loose debris would have flaked off the cliff face a long time ago.”

    Impact releases less-loose debris?

  27. @ Thorne wrote:

    So what could be breaking down the rock?

    Chemical weathering.

    http://adsabs.harvard.edu/abs/2002AGUFM.P12A0357E

  28. dcsohl

    One of my first questions when I see these photos is, what’s the scale? Well in this case, the scale is an amazing 25 cm for each pixel (on the fully embiggened image). The smallest specks visible on this image are just over a foot in size. Wow! That is something I never thought possible just a few years ago…

  29. Michel

    Made me lookup “cliff” in Wikipedia and darn, there are some mean ones right here on earth too.
    And that picture above is just going to find a place at the wall…
    somewere…

  30. Markle

    Def the best capture yet. I like how you can really see the whole path this time.

    @rob #20 I finally got to see the ISS/Shuttle with the new array this morning. It’s always been cloudy when I remembered. Predicted at -3.4 it was incredibly bright, stunningly bright. It was like a fireball in the sky and reached max brightness about 15 deg before reaching max alt. Right as it passed near zenith a 737 passed overhead on approach two fingers breadth from it and it was several times brighter than the landing lights. Put poor Venus to frickin’ shame! I watched it all the way down to the clouds over the hills. From about 20 deg down I had to use averted vision.

  31. Tom

    Was checking my email last night before bed and saw this new one. I think I got so excited about this I had trouble sleeping. Mars is such a cool place!

  32. James H.

    What are the odds that the mars orbiter would catch this many avalanches? There must be some interesting things going on there to cause this many.

  33. Thorne

    @ # 29 Sman said:

    “Chemical weathering.

    http://adsabs.harvard.edu/abs/2002AGUFM.P12A0357E

    Okay, I think I get that. I’m not a geologist, and it’s been a very long time since I had to wrap my head around that kind of chemistry (I had to look up ‘fugacity’ to make sure I wasn’t being insulted). So please forgive me if I’m too far off base here.

    But, would that kind of weathering cause the splitting and fracturing that we see from water-ice? I can visualize the weathering process, eating away at the surfaces of rocks. But can that also destabilize them? And would it do so over such a long section of the cliff? If the resolution given in #30 is correct, and if my assumption of the area which collapsed is also correct, this was a section of cliff at least 230 meters long, probably much longer! That would seem to be a lot of material for chemical weathering to account for.

    @ #28 CafeenMan asked:
    “Impact releases less-loose debris?”
    I didn’t see anything that mentioned this was related to an impact site. But yes, I would expect impacts to create a lot of debris, which would eventually collapse. But the implication here is that the avalanche was caused by erosion activities and I was simply wondering what kinds of erosion.

  34. Jeff

    This is getting to be revolutionary, because now finally spacecraft images are getting enough resolution to where you can see surface processes real time just like if an airplane was flying over the phenomena on earth.

    I agree, GREAT, GREAT, GREAT!!!

  35. Chris A.

    @Darrell E. (#17):
    “Why not be a little more accurate and say ‘700 meters (about 2300 feet)’? In this context 300 feet is significant.”

    Significant figures. I’m guessing (correct me if I’m wrong, Phil) that Phil only felt like he could trust the first digit of the published value (700 m), so he was only safe to state one significant figure. We teach it to our students, so we better walk the talk!

  36. Menyambal

    I have speculated before that some of the other “avalanche” photos were of cold carbon dioxide gas flowing of the edge of a cliff. CO2 will flow downhill here on Earth (as at Lake Nyos), and I think that it may do so on Mars, despite the mainly-CO2 atmosphere, provided it is cold compared to the atmosphere. The gas that is freshly sublimated is cold and may “burp” of the edge of a cliff and do a katabatic flow like a drainage wind. I look for evidence of that, and see that the flow lines of the dust are continuous all the way out onto the plain. It is not a rising cloud of dust all over, it is a flow down and out. The white patch at the base of the cliff may be where a continuous small flow has carried “snow” over, or preserved the snow that fell there previously.

    With this photo, in addition, I speculated that the fall was of an ice chunk, not rock or debris. The white patch at the base of the cliff may be the impact of that ice, with the dust flow from induced air flow and dislodged rock. I do not see that there is a missing chunk of fresh ice on the cliff top, though.

  37. Menyambal

    On further inspection, I do think that the fall was of ice from the ice cap. Toward the lower part of the photo, the ice cap clearly has a vertical-to-overhang edge to it. A fresh break may be the same appearance as the rest of the ice.

    The ice fell to the bottom of the cliff, and made the white patch, and dislodged rock and sand, which slid further down the talus slope, dragging air along. Any ice that rolled down the slope was discolored by sand, or may have sublimated on impact.

    Maybe.

  38. Menyambal

    Looking at the site the pictures come from, it seems obvious to me that there is cold air flowing off the cliffs often enough to leave snow with flow lines in it at the base of cliffs.

    Also, according to the text, most of the ice cap is water ice with some CO2 on top.

  39. Darrell E

    38. Chris A. Says:
    April 8th, 2010 at 11:52 am

    @Darrell E. (#17):
    “Why not be a little more accurate and say ‘700 meters (about 2300 feet)’? In this context 300 feet is significant.”

    Significant figures. I’m guessing (correct me if I’m wrong, Phil) that Phil only felt like he could trust the first digit of the published value (700 m), so he was only safe to state one significant figure. We teach it to our students, so we better walk the talk!

    Well, considering the stated resolution I would guess that the error bars are a bit smaller than that but, that is not what I had in mind anyway. I do understand, and utilize daily, the concept of significant figures, but I really don’t see a problem here with equating the 700 meters to “about 2300 feet”, even if the 7 is the only significant digit. But my main point is along a different tack altogether. We are talking about a conversion from one measuring system to another so that readers that are not familiar with conceiving of distances in meters can understand the magnitude of the value, in effect saying that 700 meters equals ___ feet. I have noticed that Phil is usually less accurate than seems warranted when he provides these types of conversions. No big deal.

  40. rob

    @JohnW (#22): it’s probably just a 5.5 cause gravity is only 0.38 gees.

  41. jcm

    caught red-handed.

    Here’s some other stuff you might enjoy: http://www.onemoreproduction.com/video/209.html

  42. Don Gisselbeck

    Does CO2 expand when it freezes? Does it drift and form cornices? Are there earlier shots of this spot at the same resolution?

  43. IVAN3MAN AT LARGE

    Don Gisselbeck:

    Does CO2 expand when it freezes?

    As far as I know, water (H2O) is the only substance that expands when it freezes; it’s that property of water that makes it unusual.

  44. DanO

    I want this in anaglyph 3D!!!

  45. alfaniner

    I’m sure it was just the Mythbusters doing some explosions for their upcoming “Mars Myths” special, on location. A REALLY high-budgeted episode!

  46. Jeffersonian

    Love it.
    Think back for just a moment about our Mars images from a couple decades back and then look at this resolution.

  47. Richard Woods

    @ Darrell E (#17 and #42),

    Regarding: “In that time I have noticed that you are very loose with numbers” and “I have noticed that Phil is usually less accurate than seems warranted when he provides these types of conversions”

    If you go to the first link Phil provided (linked from “Here is another awesome avalanche”), you will find at http://www.uahirise.org/ESP_016423_2640 that it says:

    “The cliff, approximately 700 meters (2000 feet) high is made up of layers of water ice with varying dust content, roughly similar to the polar ice caps on Earth.”

    Phil’s phrase “700 meters (2000 feet) high” is an _exact quote_ from the HiRISE webpage!

    Didn’t you check on that before you implied that Phil was responsible for the inaccuracy?

    (As for omitting “approximately”: the single significant digit conveys that sufficiently, I think.)

  48. Michael Kingsford Gray

    Wow! If that doesn’t give your spine a tingle, then you should check your pulse!
    It would be even more awesome in 3D, but I suspect that is not possible, Phil?

  49. Chris Winter

    Ho hum, another terrific picture. ;-) (Seriously, keep ‘em coming.)

    I may be wrong but it looks to me like the “up-picture” portion of the cliff (to your right if you were facing it) is ripe for collapse.

  50. Mark Kaye

    Avalanche: An avalanche is a cascade of snow or snow and ice, down a slope.

    We need new definitions for Mars. Snow or ice, a state of frozen water, does not appear to be involved with this event at all. Mudslide would involve water and soil, so that word is not right either, since water is not involved and the only “ice” in the equation is frozen carbon dioxide. This is a most akin to a rock slide.

    Great picture, all that aside…

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