BRUNSWICK — With continued low temperatures and above-average precipitation — likely even through April — experts are warning that Maine’s flood season will be delayed and could prove riskier than usual.

The annual late-winter meeting of the Maine River Flow Advisory Commission marks the beginning of Maine’s “flood season.” On Thursday, commission members said the flood risk, while currently normal throughout the state, will likely change in coming weeks as the anticipated cold causes ice to thicken and precipitation adds to the snowpack.

When temperatures eventually rise — in late March and April — all that water will begin to loosen up and run into the state’s rivers. And a fast thaw can lead to dangerous flooding.

Ideally, above-freezing days and colder nights will allow snow and ice to melt gradually, but that doesn’t appear likely this year, according to a report issued by the commission.

A period of heavy precipitation in January, followed by arctic air, has created significant ice jams in the St. John River upstream of Fort Kent, the East Branch of the Penobscot River downstream of Grindstone, the Penobscot River near Winn, the Piscataquis River upstream of Howland and the Kenduskeag Stream in Bangor, are locked in place, and additional jamming is possible once stream flows rise and ice begins to move, according to the commission, which includes members of the U.S. Coast Guard, U.S. Geological Service, National Weather Service, Maine Emergency Management Association, among other organizations..

Joe Hewitt, lead forecaster for the National Weather Service in Caribou, said Sunday that 1 to 4 inches of light snow is predicted for central and northern areas of the state beginning late Tuesday and into early Wednesday. A larger system will likely follow Thursday and Friday and could result in a significant snowstorm with wind.

“This could add quite a punch to it,” Hewitt said of the snowpack. “The latest indications are that it will be cold enough for snow all the way down into southern Maine.”

The new precipitation will add to the existing snowpack, and then temperatures will drop. A quick warm-up just after St. Patrick’s Day will be cut short by below-average temperatures through most of March, refreezing any melting ice and holding on to the already deep snowpack likely into the beginning of April.

Then, Hewitt said, depending on how quickly the thaw arrives, “There can be a problem when the release comes.”

In March of 2008, the St. John River flooded in Fort Kent after an ice jam developed and two major back-to-back precipitation events and warming hit a snowpack nearing 3 feet, according to Hewitt.

“The snowpack hung around much longer and we got really pounded in March that year,” he said. “It looks like [this] March could be an active pattern for us too.”

A March 2012 flood near Fort Fairfield occurred after an ice jam in the Aroostook River broke up quickly when temperatures reached the 70s for three days in mid-March, according to Hewitt.

“The blessing was in the thickness,” he said. “The ice was not as thick.”

This year, we may not be so lucky. While The Old Farmer’s Almanac predicts temperatures will be at or slightly above average throughout March and April, Hewitt said a “major warm-up” with temperatures increasing 10 to 15 degrees for a couple of days, or a heavy rain and higher temperatures, could prompt a flood.

“We really want to see a gradual melt, a chipping-away of it,” he said. “But the projection for a flood threat is above normal for the long term.”

Copy the Story Link