Fern-like Stellar Dendrite Snow Crystals

May 17, 2013

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Photographer: Jennifer Seay Campbell; Jennifer’s Web site 
Summary Author: Brian Campbell

The photos above show some of the delicate snowflakes that fell during a light snowfall on the night of February 2, 2013, in Salisbury, Maryland. The flakes, fern-like stellar dendrites, were huge; the biggest we’d ever seen. Jennifer, a middle school math teacher by day and also a professional photographer said, "Look at these snowflakes, I need to grab my camera!" Snow fell for about 30 minutes -- the air temperature was approximately 30 F (-1.0 C). Grabbing a chair from the kitchen table, Jennifer went out onto our deck, laid a black fabric on the deck railing and began snapping pictures (gloveless) for around 20 minutes. She used a 100 mm macro lens, a lens she purchased just to take close-ups of wedding rings.

Stellar dendrites are perhaps the largest snowflakes that fall to Earth. They’re individual crystals, not multiple flakes stuck together, and may be 5 mm or more across. Because of their wafer-like structure, snow composed of these very thin crystals can be quite powdery, even at temperatures only slightly below freezing.

Photo details: TOP - Camera Model: Canon EOS 5D Mark III; Lens: EF100mm f/2.8L Macro IS USM; Focal Length: 100mm; Focus Distance: 0.29m; Aperture: f/3.5; Exposure Time: 0.017 s (1/60); ISO equiv: 12800; Software: Adobe Photoshop CS5 Windows. Bottom - same except: Focus Distance: 0.3m; Exposure Time: 0.0050 s (1/200). Photos color corrected with Adobe Camera Raw software in Photoshop. Note that the only light source was a spotlight – photos were taken at night.