This year's mild winter and warm, dry spring has put Rhode Island at risk for a meteorological drought. This March was the warmest and one of the driest on record, and Rhode Island had experienced very little rainfall since February prior to Sunday's record-setting rainstorm. Though the weekend's storm set a daily rainfall record of 1.59 inches, total precipitation for 2012 is still about seven inches lower than normal.
The Rhode Island Drought Management Steering Committee convened April 12 for the first time in four years to discuss whether to issue a drought advisory for the state. The committee uses four different metrics to determine whether a drought advisory should be issued, said Kenneth Burke, general manager at Rhode Island Water Resources Board and member of the committee.
Precipitation levels and the area's status based on the Palmer Drought Index - a numerical representation of long-term dryness computed using data like rainfall and temperature - met the drought criteria. But deficits in groundwater and streamflow were not yet severe enough to warrant the advisory. Three of these four "triggers" must meet minimum drought conditions to issue a drought advisory, Burke said.
"If we get a bunch of rain, it could really turn things around quickly," Burke said.
Rhode Island is currently in "normal drought conditions," but the committee plans to reconvene in early May to determine whether the situation has worsened enough to warrant a drought advisory, Burke added. "We believe in all likelihood that at least one of the other triggers will be met by the end of April," he said, because some conditions that have only been present for two months must extend for at least another month to meet the drought advisory criteria.
"There's not too much in the long range for any substantial rain after this weekend," said Lenny Giuliano, Rhode Island's state meteorologist. "Dry, windy days just seem to dry up the soil even more."
Giuliano added that there are currently a number of warning signs that may indicate a longer drought. Water reservoirs, which are currently still full, could become depleted in the summer months. Only one of 38 groundwater wells is currently within normal range, and streamflows are running at about 20 percent of normal levels for this time of year, said Roy Socolow, hydrologist for the U.S. Geological Survey.
In Rhode Island, drought can have a significant impact on water-dwelling creatures including aquatic insects, amphibians, reptiles and fish, said Christine Dudley, supervising biologist in the Freshwater and Anadromous Fisheries Section of the Department of Environmental Management. Shallow streams and rivers tend to be warmer than deeper ones, and warmer streams normally have lower oxygen levels than colder streams. This means fish may be unable to meet their basic oxygen needs.
While Burke said he would hesitate to call this weather "global warming," unpredictable weather patterns are likely a result of climate change - "the new, improved word for global warming." Last spring, Rhode Island experienced "epic floods," in stark contrast to this spring, he noted.
"You're seeing warmer warm spells and drier dry spells and rainier rain events," Burke said. "It swings in both directions, and those peaks and valleys tend to be more pronounced."