Surface Hoar Crystals in Cedar Canyon, Utah
January 16, 2012
Photographer: Michael Leitch
Summary Author: Michael Leitch
This lovely feathery formation was just a smooth bed of dry snow the day before. Overnight conditions along Highway 14, a few miles east of Cedar City, Utah, were just right to create a classic example of surface hoar. A clear night allowed the snow to radiate heat and drop in temperature below the freezing point. A nearby waterfall and lack of wind provided the ambient air with moisture that, through deposition (the opposite of sublimation), formed this fairytale frost.
Surface hoar is actually common. While it can be magical in appearance, it can be deadly in some circumstances. These fragile crystals are low in tensile strength and when covered by additional accumulations of snow are the source of failure in many avalanches. The propagation saw test seen in this video provides an excellent example of how poorly a layer of hoar supports the weight of the snow above. Photo taken on December 10, 2011.
Photo details: Camera Maker: Canon; Camera Model: Canon EOS REBEL T1i; Lens: Canon EF-S 18-55mm; f/3.5-5.6; Focal Length: 24mm; Aperture: f/13.0; Exposure Time: 1/125; ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; Exposure: program (Auto); White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB; Software: Adobe Photoshop CS5 Windows (cropping; RGB input levels; and auto color).