Ice Crystals at Work in the Upper Atmosphere

There were some ice crystals in the upper atmosphere around here over the last two days, so several sky phenomena caught my attention while I was out and about. This morning, light rays from the sun reflecting off of the platy crystals produced a 22° ice halo (above), and a sun dog (below).

Last night I noticed an odd glow in the sky as the sun was nearly setting. It was a sun pillar, which is also a consequence of sunlight reflecting off of horizontal ice crystals.

Solar Pillar from the Foothills of the Sierra Nevada

We were headed home after a brief excursion into the Sierra Nevada foothills, and as we enjoyed the colorful sunset we noticed a solar pillar (or sun pillar). The pillar is caused by light reflecting off of ice crystals in the upper troposphere (the part of the atmosphere that we live in and where most weather occurs). It's maybe not the most vivid ever seen, but they always catch my attention. Now, if we could just get the auroras down south into California tonight!

No Meteors, So Some Pictures of a Sunset Instead

The Great Valley is great sometimes, but not if you want to see astronomical phenomena. We have some of the worst air pollution in the nation, along with considerable light pollution. So most years when the Perseids Meteor Shower comes along, we try to find our way up the western slope of the Sierra Nevada for some really dark skies. Besides, it hit 106 degrees yesterday, and it just HAD to be a bit cooler if we could make it a few thousand feet up into the mountains.

The sun was dropping low towards the horizon when we found a wide spot on the highway near Pinecrest Lake. It offered a really fine view towards the Dardanelles country and westward down the Middle Fork of the Stanislaus River (the opening picture of the post).

The mountains around the Dardanelles don't look like your typical Sierra Nevada peaks: they look more like flat-topped mesas in the picture above. They are not composed of granite, but instead are the remnants of lava flows and volcanic mudflow deposits that erupted from a volcanic center that was similar to today's Cascades. The difference? These eruptions were happening 9-10 million years ago, and the volcanic center died away. Erosion took over and stripped away most of the volcanic rocks except for these remnants.

We were getting a little concerned about the cloud cover. Huge thunderheads had been building over the eastern Sierra, and some clouds were starting to spill over the mountains towards the west. Lousy for looking at meteors, but maybe nice for sunset. Or a lightning show...

 The sun broke through and lit up the forest behind us and the sky to the west turned to fire.

There's not that much to say about it geologically. I suppose I could mention the sun pillar, caused by the sun's rays reflecting off ice particles in the clouds. Or I could just say enjoy the sunset...

I'm a real sucker for beautiful sunsets. Anyway, the clouds didn't clear and we didn't see a single meteor, or a flash of lightning. But I'm not complaining one little bit...

A Pillar of the Sun

Upon reading my blog, you will note that I spend a lot of time on the road, and for many reasons. One of them is that I live in a place that on a day-to-day basis is fairly unremarkable. The Central Valley of California is flat and the skies, which can often make up for flat landscapes in other places, are often equally unremarkable. We don't get many thunderstorms, or snow, or tornadoes, which is a blessing, but...unremarkable.  This time of year, the most exciting weather phenomena is fog, which obscures things. So, driving home from work this evening, I was pleased to see something interesting, a sun pillar rising from the horizon. Pillars form as the sun reflects off of horizontally oriented ice crystals in the high stratus clouds. It's not the most spectacular picture you'll ever see, but it's the best one you'll see from me today...