Puzzling triple rainbow clearly identifies location of pot of gold

I noted to some friends that the weather forecast for Seattle two weekends ago called for rain on Friday, rain on Saturday, and rain on Sunday. But at least on Monday, the forecast was not for rain.

It was for heavy rain.

One of the consequences of Seattle's annual Rain Festival (runs from January 1 to December 31) is that we get plenty of potential for rainbows. A friend of mine was lucky enough to capture a photo of a puzzling triple rainbow this past weekend. The primary and secondary rainbows we all know about, but what's that vertical rainbow shooting straight up into the sky? (And observe that the landing point of the rainbow is clearly in front of a house and trees, so go get your pot of gold.)

It turns out that the mysterious third rainbow is a reflection rainbow. Reflection rainbows occur when light bounces off a body of water before being refracted by rain droplets. The body of water acts like a mirror and creates a virtual light source, which results in a rainbow that is off-center from the primary.


(I find it interesting that there are some rainbow phenomena that science is still trying to understand. Only a few months ago did researchers figure out how twinned rainbows are formed.)

Bonus reading: Seattle weather celebrity (yes, we have weather celebrities here) Cliff Mass digs into the triple-rainbow phenomenon, augmenting his analysis with Doppler radar, because that's how he rolls.

Comments (11)
  1. Matt says:

    Ah yes, Seattle might be rainy, but only in the UK do we have dedicated live coverage of the weather


  2. Adam Rosenfield says:

    The coolest rainbow I ever saw was in the water coming out of a snow gun at a ski resort.  I was sitting up on a chairlift and saw the entire circle of the rainbow.  Unfortunately, I wasn't able to get out my phone in time to snap a picture, and the next time I rode the lift up, it was gone.

  3. voo says:

    The Raymond effect apparently has killed the linked blog :-)

  4. Solarbird, the Lightbringer says:

    Yeaaaah, kinda. We're up! We're just slow. The webserver is fine! We're sitting at a comfy 3% of CPU and aren't even hitting swap. Comcast, tho'… not as much. XD

  5. Solarbird, the Lightbringer says:

    We've moved some wires around; it should be better now. It's testing better for us, anyway.

  6. Squire says:

    Rainbows and Double Rainbows – Sixty Symbols

    The physics of rainbows with Professor Mike Merrifield.


  7. Mike Edenfield says:

    Are your weather celebrities the same as the ones we have here in Florida? Here, the news goes something like this:

    News Anchor> And now, over to chief meteorologist Frank Hurricane for the weather.

    Frank> Tomorrow's forecast is partly cloudy, high in the mid 90s, 50% chance of brief showers in the afternoon, cooling to the low 70's over night. Back to you.

    News Anchor> Way to go out on a limb there Frank.

  8. j b says:

    Adam Rosenfield,

    I guess that chairlift was quite high up in the air, and you were looking down on that snow gun, right?

    When you see full circle rainbow (raincircle?), the lightsource (i.e. the sun), your eyes and the circle center lies on a straight line. Unless you are high up in the air (such as in an airplane) and the sun is very low, the major part of the circle will be below the horizon. That is for a "natural" rainbow, where the reflection happens in droplets in the atmosphere.

    In your case, where the light was reflected in ice crystals / snow from the snow gun, I guess that the reason why you were able to see it at all is that the background was white snow. I cannot imagine that it would be visible against a dark forest! Conditions must have been extremely favorable – a once-in-a-lifetime experience.

  9. Dave T says:

    I have a new favorite music genre: Rage-driven acoustic elfmetal.  The Something's Coming video was cool.

  10. JAHA says:

    What does it mean!!!?

  11. Mason Wheeler says:

    The "vertical rainbow" doesn't look vertical to me. It's clearly curved if you look at the top and the bottom; it's just part of a much larger circle than the other two, so the curvature is less noticeable.

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