Earliest recorded ice-out is declared at Winnipesaukee

Spring is still a few days away, but it’s officially ice-out on Lake Winnipesaukee.

The announcement was made on Sunday, the earliest an ice-out has ever been declared at the New Hampshire lake. An iceout is announced when the ice has thawed enough that the M/S Mount Washington, a 230-foot ship that gives scenic cruises around the lake, can sail to all five of its ports: Center Harbor, Wolfeboro, Alton, Weirs Beach, and Meredith, N.H.

It also marks the unofficial start of spring, and the beginning of boating season, in the state’s Lakes Region, just south of the White Mountains.

As New England winters warm, lake ice has dwindled. In Vermont, lakes and ponds have been thawing about three days earlier each decade, on average, since 1988.

Emerson Aviation made the announcement on Sunday at 4:37 p.m., according to the company’s Facebook page. The earliest ice-out had been March 18, 2016. The latest documented ice-out was May 12, 1888.

Emerson only declared an “ice-in” on Feb. 9, according to WMUR.

Decreasing ice coverage is a concern of the Lake Winnipesaukee Association, a nonprofit organization dedicated to protecting the lake’s water quality.

A shorter ice-covered period results in warmer water and a longer time period for plant growth, including algae and cyanobacteria, said Bree Rossiter, the group’s conservation program manager.

“These changes in water temperatures can significantly impact the lake’s ecology, benefiting some species but negatively impacting others, such as coldwater species like landlocked salmon and trout,” Rossiter said in an email. “An extended summer season may be welcome to many but brings added concern regarding invasive species and will provide favorable conditions for cyanobacteria blooms. These shifts in our lakes emphasize the need for protection and preservation of our water bodies now.”

Emerson Aviation has been flying over Lake Winnipesaukee and making ice-out declarations for decades.

“We took over in 1979 when the late Bob Aldridge, a fellow pilot and Gilford Rotary member, showed us what he looks for and handed off the reins,” said David A. Emerson, president of Emerson Aviation, by email.

In April 1952, the Globe published a story about the significance of ice-out in the Granite State.

“There are two cries heralding the advent of spring in New Hampshire,” the Globe reported. “The first comes from the (maple) sugar bush and is ‘sap’s runnin’. ‘Just a few weeks later, the equally enthusiastic cry ‘ice is out’ is sounded. In rural New Hampshire, regardless of what the almanac says, Spring isn’t officially here until ice-out.”

In the 1952 story, the Globe noted that in 82 years of recordkeeping (which would date back to 1870), the ice-out had occurred 53 times in April, 27 times in May, and only twice in March.

The previous earliest ice-out was March 18, 2016. The latest documented iceout was May 12, 1888.

Material from previous Globe stories was included in this report. Emily Sweeney can be reached at emily.sweeney@globe.com. Follow her @emilysweeney and on Instagram @emilysweeney22. Carlos Muñoz can be reached at carlos.munoz@globe.com. Follow him @ReadCarlos and on Instagram @Carlosbrknews.