Bitter Cold Temperatures and Rime Ice in England

February 25, 2013

Hoar Frost (2)

Photographer: Kiran Chakravarti; Kiran's Web site
Summary Authors
: Kiran Chakravarti; Jim Foster

The United Kingdom endured extremely cold conditions in December 2012. A meteorological phenomenon called Sudden Stratospheric Warming was partially to blame. On occasion, warming of the stratosphere can result in sub-freezing temperatures at the surface. It's unusual for such cold weather to last so long in southeast England -- snow and ice were still thick on the ground even into January, 2013.

While on a frigid walk in Hertfordshire, England, in mid December, I noticed that the edges of evergreen leaves were coated with an exquisite fringe of icy, needle-like protrusions -- rime ice. Riming occurs when supercooled water droplets in ground fog comes in contact with objects at temperatures below freezing. If the fog is thick or windblown, layers of rime will continue to build, as in this case, into the needle-like formations. Photo taken on December 12, 2012.

Photo details: Camera Model: Canon EOS 450D; Lens: EF-S18-55mm f/3.5-5.6 IS; Focal Length: 32.0mm; Aperture: f/4.5; Exposure Time: 0.0050 s (1/200); ISO equiv: 400; Flash Fired: Yes (Auto, return light detected).