'Ice-Out' Times A Harbinger of Spring, And Lake Health

Apr 24, 2019

Emerson Aviation declared April 24, 2019 as the official "Ice Out" date on Lake Winnipesaukee.
Credit Emerson Aviation

Wednesday marked "ice-out" on Lake Winnipesaukee – the day when the cruise boat Mount Washington can safely reach all of its ports.

It's pretty standard timing for this traditional sign of spring. But overall, state records say New Hampshire lakes and ponds may be thawing earlier as temperatures warm.

Sara Steiner runs a state program that tracks water quality data for New Hampshire lakes and ponds. And she says the ice-covered season plays an important role in a water body’s health.

“It gives our lakes a chance to sort of recuperate,” she says.

Steiner is gathering decades of data on ice-outs across the state. So far, these records show a slight trend toward earlier ice-outs – including on Lake Winnipesaukee.

“That generally means that our lakes are exposed to more pollutants for a longer period of time,” Steiner says.

It can also affect oxygen levels, plant growth and recreation, she says.

"If we have ice-out that's happening earlier, then yes, we have a longer season where our lakes are being utilized,” she says.

But Steiner says a lot more data is needed to fully illustrate the trend.

For one thing, she says ice-in dates – which mark the start of the fully frozen season – are reported much more rarely than ice-outs.

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