I just took this picture out my window about five minutes ago. There was a light thunderstorm earlier in the day, and the remaining clouds appear blue on the bottom! The white area near the top is not a cloud, but rather it is where the sun is poking through. Notice the typical orange sunset peeking through near the horizon. The digital pic doesn’t do it justice; it’s a really deep, saturated blue. And just my luck, I ran out of Fuji Velvia.
It’s a stunning effect, but I don’t think I’ve ever seen it before. What could be causing it? Sadly, it seems to be going away now.
It could be from pollutants like sulpher (acid-rain) but is probably just ice particles in the clouds. They change the wavelength in which the light is reflected and shine as a brilliant blue, IIRC.
I don’t mean to dismiss the wonder and awe of the OP, but what’s so unusual about that picture? Or is there something that was lost in the conversion from real life to jpg? I’m sitting in Logan Airport right now, and outside I can see clouds that look blue.
I suppose crystals would be the correct term when referring to ice. But I’d guess those clouds are the products of the recent cold and warm fronts clashing. The temperature in those clouds would definitely be near freezing. We got some hail here as well.
I hear ya R/J but I’m not an expert on the weather in Queens. It’s pretty common here in the damned tornado alley. Warm and cold fronts from the Gulf of Mexico battle the Arctic blasts down through the plains. It is probably a common sight along the Pacific coast with those damned hot winds from Mexico slamming into the cold coming down from the mountains of Northern California. Then again, not everyone has their head in the clouds like some of us.
Plus the question was what causes the blue color. At least he didn’t ask why is the sky blue.
I’m just razzin ya freido no offense intended. It was a nice picture though.
Water is blue… air is (slightly) blue… I think the real question is, why aren’t ALL clouds blue?
But seriously, it probably has to do with the angle of the sunlight. Clouds are generally white or grey because the sunlight is coming down at a more-or-less vertical angle, and gets scattered randomly by the clouds. When you took your picture, the sunlight was coming in close to horizontally and you were seeing only the light that was bent so-many degrees “down” when it refracted through the cloud.
Water and air are transparent and take the color (to our eyes) of the light they reflect. Water in the sea is blue if the sky is blue, but black if the sky is black. But your reasoning for the blue color in the clouds appears reasonable to me.
Clouds generally appear white or gray because that’s the color reflected by the water droplets or ice crystals. On an overcast day, the clouds appear gray because the sunlight is unable to penetrate through. They appear whitish if they reflect the sunshine. Clouds are just water droplets or ice crystals.
Clouds are white due to transmitted light, not reflected. White light is scattered and attenuated by the clouds, and the more attenuation that occurs, the “greyer” the cloud appears.
