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Warily Watching the River Flow

An unexpected thaw caused ice buildup and high water below the Cornish-Windsor covered bridge on Wednesday, January 16, 2014. (Valley News - Elijah Nouvelage)

An unexpected thaw caused ice buildup and high water below the Cornish-Windsor covered bridge on Wednesday, January 16, 2014. (Valley News - Elijah Nouvelage) Purchase photo reprints »

Cornish — Neighbors and emergency officials are keeping a watchful eye on the Connecticut River near the Cornish-Windsor Covered Bridge, where long-time residents say ice jams recently reached their highest level in years, maybe decades.

“Man, it’s getting high up there!” West Windsor resident Mike Allen recalled remarking to his wife as they drove over the bridge to 12% Solution convenience store Thursday.

Standing in the store parking lot, Allen said ice jams this past weekend caused the river’s chunks to rise to the highest point he’s seen in quite some time.

“Probably since ’94, ’95, it’s been that long,” said Allen, 43, who grew up in Windsor. “It’s getting scary.”

Ice jams occur when icy rivers thaw just enough to break into chunks, but not enough to melt entirely. The chunks can then collect around bridge pillars or bends in the river, causing them to build up and stifle water flow, as was the case in Cornish this weekend.

That scenario can cause flooding upstream. Flash flooding can also occur downstream when an ice jam suddenly shifts and releases a torrent of water that has been dammed up.

Cornish Police Chief Doug Hackett said the river’s ice on Sunday reached within a few feet of the underbelly of the bridge — “closer than I’ve ever seen it,” he said — estimating it was at its highest mark in at least a decade.

Selectboard Chairwoman Merilynn Bourne said it’s been even longer. The last time the ice-jammed river reached that high, she said, was in March 1979, when a few of the ice chunks ended up on Route 12A.

Just years earlier, in 1977, “you had to get to the bridge and the houses right by the bridge by boat,” Bourne said in an email. “(Route) 12A just south of the bridge was under water, and the store now known as 12% Solution had water in the store.”

Emergency officials said they monitored the situation closely on Sunday, when ice from the river crept up to the fog line (the road’s outer white line) on Route 12A. The ice has since receded, but Cornish Emergency Management Director Paul Whalen noted that it could rise again as conditions change.

Upstream from the Cornish covered bridge on Thursday, the river’s surface was covered in stationary chunks of ice. But water could be seen flowing under the bridge and appeared at the surface to be flowing under more ice chunks downstream.

Hackett and Whalen said that local officials were joined on Sunday by representatives from New Hampshire Department of Transportation and the pipeline company TransCanada, which operates dams along the river. Several onlookers were also out at the bridge taking pictures, Whalen said.

Whalen said TransCanada was able to estimate the rate of water flowing at the Wilder Dam upstream, as well as the rate flowing downstream at a dam in Bellows Falls, Vt. The fact that water was steadily flowing through both dams signaled that the river was continuing to flow smoothly beneath the ice chunks and did not pose an imminent risk of flooding, Whalen pointed out.

TransCanada spokeswoman Sharan Kaur said the river and ice jams are “being patrolled all over our facility. ...

“Whenever the temperature changes, we continue to make sure that we’re out there and looking at it,” she said, adding in an email, “In the event that an ice jam breaks apart and the flow increases, we do have the ability to open our flood gates to help the ice pass and keep the flow moving.”

Windsor ambulance services in Vermont cover part of Plainfield across the river in New Hampshire, and so mutual aid plans are in place in the event Route 12A floods or the bridge is rendered unusable, Whalen said.

Farmland on the Vermont side of the river has been flooded, but Windsor Town Manager Tom Marsh said risks to infrastructure are less of a concern there because the banks are higher than on the New Hampshire side and there is more space between the river and the roadway.

Claremont firefighter James Chamberlain said emergency officials implemented a full-time watch Sunday on the Sugar River, which was also rising because of ice jams, but has since receded.

Another long-time area resident, Nancy Lawrence, said she wants to make sure officials are closely monitoring the Connecticut river to ensure unsuspecting motorists aren’t surprised by road flooding.

Lawrence, 67, has “lived on the river (her) whole life,” she said; she was born on River Street in Windsor and lived there until she married and moved to Route 12A in Plainfield. She agreed that this week’s ice jam is notable not only for its height, but also for its duration.

“It’s a very big ice jam this year,” she said. “And it seems it’s lasted like longer than any one I’ve seen.”

The Upper Valley is not the only region under threat of ice jams, as meteorologists said arctic air blowing in from the polar vortex created icy conditions that later melted and caused jams in Niagara Falls.

Although the Niagara Falls jams are not expected to cause “significant problems,” another round is forecasted toward the end of the month, according to a news release from weather website AccuWeather.

Maggie Cassidy can be reached at mcassidy@vnews.com or 603-727-3220.

Related

Letter: Dangerous Ice Jam in Cornish

Tuesday, January 21, 2014

To the Editor: I would like to know if anyone besides me is worried about the big ice jam on the Connecticut River in the Windsor/Cornish area? This is one of the worst jams I have seen in my years. I fear for innocent unsuspecting motorists traveling 12A should they be caught there as the ice moves, as I’m sure …