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