Hoarfrost in Helena, Montana

December 22, 2010

Photographer: Martin Richard
Summary Author: Martin Richard; Jim Foster

Those residents of Helena, Montana who got up early on December 5, 2010, and looked outside may have been charmed to see the landscape covered in hoarfrost. Hoarfrost contains larger crystals than the rather tiny frost crystals that often form on very cold nights. They’re larger because they’ve acquired additional water vapor; the source of this vapor may be an unfrozen river or lake or a layer of fog. The crystals increase in size as vapor freezes on their protuberances.

Alas, this lacy hoarfrost quickly sublimated in the sunshine, faster than a melting witch. On this morning, clouds were to the east and the Sun was just rising above them, illuminating Mount Helena (in the distance), but not returning the frosty moisture to the atmosphere. There was no time to waste if I wanted to capture such transient beauty. I live adjacent to a park here in Helena, and my early rising neighbors likely raised an eyebrow or two at the camera-carrying nut in a bathrobe and white rubber snow boots slogging through the park. In spite of their stares, I captured my quarry. Photo taken December 5, 2010 at 8:25 a.m. The view is to the southwest of Mount Helena. 

Photo Details: Camera: NIKON D300S; Lens: 18.0-70.0 mm f/3.5-4.5; Focal Length: 48mm (35mm equivalent: 72mm); Focus Distance: 3.98m; Aperture: f/4.5; Exposure Time: 0.0020 s (1/500); ISO equiv: 200