Thursday afternoon, 04 February 2010, cirroform clouds filled the sky ahead of an approaching winter storm. At first I noticed a couple of parhelia, also known as “sundogs.” A while later, I saw a circumzenithal arc high in the southwestern sky. By the time I walked home to get a digital camera, the phenomenon had disappeared. See what you missed by looking at a gallery of photos of circumzenithal arcs taken by other photographers.
Friday morning, snow started falling around 10:00 a.m.; 24 hours later, snow is still falling and the National Weather Service has posted a winter storm warning effective until 10:00 p.m. Saturday, 36 hours after the storm began. So far, some parts of the Washington, D.C. metropolitan region have recorded up to 30″ of snow! Overnight, my neighborhood lost power twice: the first time, the power was off for about 30 minutes; the second time, the power was off for several hours. During the second outage, it was pitch black outside. I saw numerous lightning flashes, but never heard thunder. Meteorologists call this phenomenon “thundersnow.” Essentially, thundersnow is a thunderstorm during a strong winter storm.