RECORD SPRING 2012 HEAT WAVE ACCENTUATES A HISTORIC TREND TOWARD EARLIER ICE LOSS AND INCREASED TEMPERATURES IN WEST VIRGINIA COLD-AIR TRAPS
A journal of annual holiday ice-cream making has shown Little Beartown ice persisted until after July 4th every year between 1985 and 1999, but only about half of the years since 2000. Hobo Pendant data and field observations show the disappearance of near-surface ice approximately correlates to the date when temperatures rise above +1˚C for the season. This +1˚C threshold has been crossed earlier in each of the last four years, punctuated by ice loss at Little Beartown on or about May 17thin 2012.
Nearly 10 years of continuous Hobo measurements at Ice Mountain shows a mean July 4thtemperature increase of ~1.8˚C between 2003-2009 and 2010-2012. Temperatures rose above +1˚C at two cold air vents in April 2012, a full 27 days earlier than any of the preceding nine years. Early June 2012 temperatures were 4.3˚C warmer than average, and 3.1˚C warmer than the previous record high.
Although accounts of ice lasting into September were common over a century ago, 21st Century measurements show both sites have cave-like (9 to11˚C) temperatures with little variability at the end of the water year. In 2012 temperatures approached seasonal averages through summer, and by September were only 0.2˚C and 0.3˚C above average at Little Beartown and Ice Mountain, respectively.