Ice storms are powerful, frightening, and curiously aesthetic extreme winter weather events. Between Jan. 18 and Feb. 11, a team of researchers created a suite of experimental ice storms at the Hubbard Brook Experimental Forest near Woodstock, N.H., in an effort to better understand the effect of ice storms on tree growth, susceptibility to pests and pathogens, changes in habitat for wildlife, and how nutrients like carbon and nitrogen cycle in the forest.

Photo credit: Joe Klementovich, Courtesy of Hubbard Brook Research Foundation

How do you create an ice storm?  It takes planning as well as a dependable supply of water, fire hoses, high pressure pumps, generators, and   freezing  cold temperatures.

Photo credit: Joe Klementovich, Courtesy of Hubbard Brook Research Foundation

The research team at Hubbard Brook Experimental Forest spent a year preparing for this winter experiment, including studying the biology and chemistry of the trees, insects,  birds and soil on the plots; training all participants in snowmobile and winter exposure safety; and completing three  practice storms at other sites under a range of conditions to ensure that water pumps and other equipment would operate properly under extreme conditions.

The scientists then had to wait patiently for the weather to finally get cold enough in this El Nino year for the Ice Storm Experiment. Scientists needed several consecutive days with highs of 20 degrees and lows in single digits, which finally started happening  on Jan. 18.

Photo credit: Joe Klementovich, Courtesy of Hubbard Brook Research Foundation

Researchers created experimental ice storms on Jan 18, Jan 27-29, and Feb 11, 2016.  Altogether they iced eight plots, each of which were 60 x 90 ft or roughly the size of a college basketball court.  Two plots were iced with radial ice accretions of ¼”, four plots with radial ice accretions of ½”, and two plots with radial ice accrertions of ¾”, approximating light, medium and heavy icing events.

It took 1-4 hours to spray each plot and several hours to move sprayers, vehicles and people from one plot to another. 

Photo credit: Joe Klementovich, Courtesy of Hubbard Brook Research Foundation

In order to spray at the coldest time of day, scientists and their teams sprayed well into the night, aided by high intensity LED spot spotlights.

Photo credit: Lindsey Rustad, US Forest Service Northern Research Station

Scientists continued working after the icing was completed to make detailed measurements of ice accumulation.

Photo credit: Joe Klementovich, Courtesy of Hubbard Brook Research Foundation

Ice accumulation, or accretion, was measured using wooden “ornaments,” with arms meant to simulate tree branches but with uniform surface and dimensions. The ornaments were hung high up in trees within the two research plots and adjacent control plots. The goal of the experiment was to create a suite of perfect ice storms, ranging from ¼” to ½” to ¾” of radial ice accretion. The ice measured on the wooden ornaments proved that the scientists achieved their goal.

Photo credit: Lindsey Rustad, US Forest Service Northern Research Station

Scientists will now spend the next several years to decades watching  and studying the impacts of these simulated ice storms on a range of forest effects.

Photo credit: Lindsey Rustad, US Forest Service Northern Research Station

Ice storms are expected to become more frequent and severe in the northeastern United States and eastern Canada as long term climate continues to warm while short term. Weather patterns still bring blasts of arctic air into the region. In addition to literally reshaping the forest, ice storms disrupt lives and damage infrastructure in towns and cities in northern New England, resulting in billions of dollars of damage.

Photo credit: Lindsey Rustad, US Forest Service Northern Research Station

The team of scientists for the Ice Storm Experiment include Lindsey Rustad, a research ecologist with the Forest Service’s Northern Research Station and Team Leader at Hubbard Brook Experimental Forest; John Campbell (pictured) research ecologist with USDA Forest Service; Charley Driscoll, Syracuse University; Paul Schaberg USDA Forest Service; Katharine Hayho of Texas Tech University; Sarah Garlick of the Hubbard Brook Research Foundation; Peter Groffman of the Cary Institute of Ecosystem Studies; Timothy Fahey of Cornell University; and Robert Sanford and Joe Staples of the University of Southern Maine.

Photo credit: Joe Klementovich, Courtesy of Hubbard Brook Research Foundation