Icicle Daggers

January 31, 2010

IceDaggerswithInset (2)
: Carl Crumley
Summary Author
: Carl Crumley; Jim Foster

A few weeks ago, I was driving down a street in Rochester, New York and out of the corner of my eye saw something floating in mid air near someone's front stoop. I turned around and went back to take a closer look. By golly it was a clump of icicles that had evidently broken loose from the corner of the house and slid down a wire that happened to be going right through the middle of the clump. The day before I snapped this photo, Rochester had its first above freezing weather of the new year -- the maximum temperature was 43 degrees F or 6 C. Because temperatures remained above 32 F (0 C) throughout the day, some icicles grew to prodigious lengths. These icy daggers, and the fact that an electrical wire is going through them, were likely pretty effective in keeping even the most fervent salesman from knocking at the front door of this house.

Big icicles are associated with damaging ice dams. Both generally result from poor insulation and air leaking from the living area of a house into the attic space. When snow on the roof melts off, the melt water then moves down-slope until it reaches the colder, non-insulated, overhang. Here, it’s more likely to refreeze, forming icicles and ice dams that eventually force the melt water to back up under the roof’s shingles. Structural damage, mildew and mold may well ensue. Photo taken on January 14, 2010.

Coordinates for Rochester, New York  43.155125, -77.614975

Earth Observatory image: Snow in time for the solstice