ANDOVER, Maine — Above-normal temperatures in the mid-70s on Friday combined with heavy rain Friday night into Saturday morning to melt snow and drive the Ellis River over its banks.
By 11:45 a.m., the river was encroaching on a banked section of the Covered Bridge Road, where the low end of the road (the westbound lane) dips toward the riverbank.
And, for a few hundred wood frogs emerging from their winter’s sleep under the leaf litter, the rain and warmth raised the water level of their vernal pool near Andover’s Lovejoy Covered Bridge.
The tiny frogs, which sound like quacking ducks when advertising their location for breeding, sang at full chorus, drowning out the lone spring peeper in their midst.
While the National Weather Service in Gray didn’t issue a minor flood warning for the Ellis River on Saturday, it did issue a winter/spring flood potential outlook for the next two weeks.
Hydrologist Tom Hawley’s Hydrological Data bulletin said the flood potential was slightly above normal in Maine’s mountains.
However, the flooding potential due to ice jams in western Maine has passed.
Hawley said that with above-normal temperatures expected and a more active weather pattern, rivers will be rising slowly as the remaining icepack melts.
“It is important to note, however, that major flooding does not occur from snowmelt alone,” Hawley said.
“Rainfall — how much and in how short a period of time — is the most important factor in determining the severity of flooding,” he said.
He said that over the past two weeks, the blocking pattern that has affected the Northeast has slowly broken down, allowing milder temperatures to move into northern New England.
Hawley said the official six- to 10-day forecast calls for above-normal temperatures and above-normal precipitation. The eight- to 14-day forecast calls for normal temperatures and normal precipitation, he said.
Snow is now confined to Maine’s mountains, with depths ranging from 2 to 15 inches, Hawley said.
Snow surveys done by Brookfield Power on April 15 at 1,700 feet elevation at Parlin Pond near Jackman showed 31 inches of snow with 14.6 inches of water equivalent, Hawley said.
Reservoirs in the Androscoggin River basin are 45.9 percent full, which is 0.9 percent above normal, Hawley said.
Those factors help the weather service assess Maine’s flooding potential.
The Androscoggin River at Rumford was over its banks in a few backwater locations beside Route 2. But at Brookfield’s dam, it was 4½ feet below the 15-foot flood stage and expected to rise to nearly 11 feet by 7 a.m. Sunday, according to the weather service’s Daily River and Lake Summary issued Saturday afternoon.
The National Weather Service issues winter/spring flood potential outlooks every two weeks until the end of the snowmelt season. Hawley said the next one will be issued at 8 a.m. Friday, May 3.