AUGUSTA — Cold air, a stubborn snowpack, thick river ice and a forecast that includes snow and rain have emergency managers keeping a wary on the state’s rivers.
While there is little to indicate the region is at an increased risk of a historic flood on the level of 1987, National Weather Service officials during a Thursday state River Flow Advisory Commission conference call agreed that the potential for ice jams and open water flooding is there.
“There is above-normal flood potential in most of the state,” said Tom Hawley of the National Weather Service in Gray.
Gregory Stewart, data section chief for the U.S. Geological Survey in Augusta, said he has been telling people that the calendar is broken.
“I think we’re two or three weeks off,” he said. “These are the conditions I would expect in early March.”
Stewart said the region is beginning to get normal runoff and slight increases in water temperature, but it is occurring a couple of weeks late. The difference has been enough to wash away slush from the Kennebec River, which is key because slush is an important factor to creating ice dams. Stewart said the weather pattern, while cold, has been of late more conducive to flood prevention.
“We’re seeing exactly what we want to see, warm days and cold nights,” he said.
But that could change over the next several days.
Forecasters are calling for sun and temperatures near 60 on Friday followed by rapid cooling and a weekend storm that threatens to bring rain and snow to much of the state. Stewart said the Friday warming will melt the snowpack, which is unusually deep in the woods, and prime the rivers. The rain will add unneeded water to the mix. The result will be an increased potential for ice jams in rivers throughout central Maine. Stewart said the slush already released by the Kennebec River gives him less concern about that river.
The forecast for the next several days calls for below-normal temperatures, but Stewart said the pattern of daytime ice melt and nighttime cold should put the region in good shape.
“After this weekend if we don’t have ice jams we should be in good shape,” he said.
U.S. Coast Guard ice cutters came up the river to Gardiner on Wednesday, reporting ice conditions averaging 6-12 inches “with thinner ice reported near Gardiner,” according to a Thursday email update from Lt. David Bourbeau, the Coast Guard’s waterways management chief in Maine.
Crews left Gardiner on Thursday morning and were prepared to break up any ice jams they encountered on the way back down the river.
“The Kennebec River is reportedly flushing very well with heavy ice flows reported in Bath,” according to Bourbeau.
Hawley said the slow melt should continue into next week. Below-normal temperatures are expected through early next week, and there is a potential for snow or rain midweek, but temperatures are expected to rise to near-normal highs in the early 50s by the end of the week.
Bob Marvinney of the Maine Geological Survey said the open fields beginning to pop up around central and southern Maine are misleading when it comes to determining snowpack.
“When we go in the woods there’s still a lot of snow there,” he said.
Rain adds water content to that snow, leaving the potential for a lot of water if there is a rapid runoff.
“We’re getting close to the conditions that will lead to rapid snow melt,” he said.
The snow is hanging around much longer than usual because of below-normal temperatures.
Maureen Hastings of the National Weather Service in Caribou said the longer that happens into the spring, the more risk there is that a drastic warm-up would lead to fast melting and rain and the accompanying rush of water. It is too soon to know if that will happen, but officials agreed to hold another conference call in two weeks to reassess the picture.
“Our long-range models can’t quite agree on what they say is going to happen,” Hastings said.
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