Lake Auburn sets records for earliest ice-out, least amount of days with ice cover

Lake Auburn shows open water during a rainy March day in Auburn. The ice-out, on March 13, was the earliest on record. Andree Kehn/Sun Journal

AUBURN — Lake Auburn set two ominous records last week, marking the earliest ice-out and least amount of days with ice cover since record-keeping began.

The records fell in a year in which most of Maine’s lakes and ponds saw very short periods of ice cover due to a mild winter, but that has local water quality experts on guard as spring and summer arrive.

Erica Kidd, watershed manager for the Auburn Water and Sewerage Districts and Lewiston Water Division, said the March 13 ice-out date was the earliest they have on record going back to 1836. The total number of days between ice-on and ice-out — 55 — is also the “shortest duration of ice cover we have seen since ice-on data started being recorded in 1953,” she said.

Mike Broadbent, Auburn Water and Sewerage Districts superintendent, said staff does not perform any additional or specialized work due to the early ice-out, but that they do start sampling lake water earlier.

In 2023, the lake also broke a record with its latest ever “ice-in” date. It took until Feb. 1 of last year for the lake to completely freeze over. Water district staff told the Sun Journal last year that they “sleep better” the longer ice cover remains on the lake.

As the average duration of ice cover declines, researchers are increasingly concerned for long-term water quality. Bates College professor Holly Ewing, who has continuously studied Lake Auburn, has said the shorter periods of ice cover “means there is more time with lots of light and warmth for organisms to grow in the lake.”

And Lake Auburn is already susceptible to algal blooms, which are caused by more nutrients like phosphorus entering the watershed during large rain storms. According to water district staff, sediment in the watershed is already naturally high in phosphorus content due to a mineral called apatite.

Since 2006, Lake Auburn has experienced a total ice cover of 70 days or less six times. Prior to that, it had never happened. Before the year 2000, the shortest duration of ice cover was 90 days, set in 1953. The lake hasn’t reached 90 days of ice cover in the past four winters.

The alarm bells raised by researchers like Ewing over the last few years have caused officials in both Lewiston and Auburn to rethink their approaches to watershed protection, and disagreements over how to handle future development.

Last year, the Lake Auburn Watershed Protection Commission hired a consultant to identify large sources of phosphorus in the watershed, and there have been ongoing talks with the upper watershed towns of Turner, Minot, Hebron and Buckfield regarding water quality protections.

Watershed officials are also monitoring whether they will have to conduct another aluminum sulfate treatment in the lake due to high phosphorus levels. The treatment, last done in 2019, binds to phosphorus and settles to the bottom of the lake, making the nutrient less accessible to algae.

Broadbent said the water district does not yet have an “alum” treatment planned, but said, “we’re monitoring conditions continuously.”

According to recent analysis from the Morning Sentinel, a large number of Maine’s lakes and ponds marked ice-out roughly a month earlier than 2023. State officials told the Sentinel that earlier ice-outs also have severe impacts on trout populations, ticks, moose calves and recreation like snowmobiling.