Massive waves in Maine

Massive waves a mystery at Maine harbor

http://cache.boston.com/resize/bonza..._8833/539w.jpg Owen Johnson (left) and his father, Peter, repaired damage yesterday done by waves in Boothbay Harbor. (Joel Page for The Boston Globe)

By Megan Woolhouse
Globe Staff / November 4, 2008

Dockworker Marcy Ingall saw a giant wave in the distance last Tuesday afternoon and stopped in her tracks. It was an hour before low tide in Maine's Boothbay Harbor, yet without warning, the muddy harbor floor suddenly filled with rushing, swirling water.

In 15 minutes, the water rose 12 feet, then receded. And then it happened again. It occurred three times, she said, each time ripping apart docks and splitting wooden pilings.

"It was bizarre," said Ingall, a lifelong resident of the area. "Everybody was like, 'Oh my God, is this the end?' " It was not the apocalypse, but it was a rare phenomenon, one that has baffled researchers. The National Weather Service said ocean levels rapidly rose in Boothbay, Southport, and Bristol in a matter of minutes around 3 p.m. on Oct. 28 to the surprise of ocean watchers. Exactly what caused the rogue waves remains unknown.
"The cause of it is a mystery," said National Weather Service meteorologist John Jensenius, who first reported the waves from a field office in Gray, Maine. "But it's not mysterious that it happened."
Specialists have posed a variety of possible explanations, saying the waves could have been caused by a powerful storm squall or the slumping of mountains of sediment from a steep canyon in the ocean - a sort of mini tsunami. The last time such rogue waves appeared in Maine was at Bass Harbor in 1926.
Jensenius said the occurrence is so unusual, that specialists don't have a name for the phenomenon.
"That's part of our problem," he said.
A similar occurrence in Florida more than 15 years ago continues to baffle researchers. A series of 12- to 15-foot waves hit Daytona Beach on July 3, 1992, injuring more than 20 people and lifting and tossing dozens of cars.
Jeff List, an oceanographer at the US Geological Survey at Woods Hole said he and other researchers studied the occurrence, but no one has been able to pinpoint the cause. And he said similarly enormous waves appeared once on the Great Lakes.
Could such a wave or waves enter Boston Harbor, or even engulf the Massachusetts coast?
"It seems a little unlikely one could hit Boston," List said. "But then again, these things are always surprises when they occur."
A squall line surge, which occurs when fast-moving storm winds sweep over water that is traveling the same speed, can create such a wave. (The speed of waves is directly related to wind speed and the depth of the ocean at any given point.)
List and other specialists said such an occurrence is exceedingly rare, but when it occurs, "you get this interaction that causes a large bulge of water to rise up."

Jensenius said that might have been a factor last week, when a major storm front brought rain to most of the East Coast, particularly southern New England. But he said that does not solve the mystery, adding that he had not ruled out a massive "land slump" underwater. Such slumps can create waves that may be classified as tsunamis, although no where near the size and scale of the tsunami that occurred in the Indian Ocean in 2004. Those fast-moving and deadly waves were caused by a massive earthquake.
Tsunami-like waves may not be as rare on the East Coast as most people think. Jensenius referenced a 2002 article in the International Journal of the Tsunami Society that called the threat of tsunami and tsunami-like waves generated in the Atlantic Ocean "very real despite a general impression to the contrary."
The article said such waves appear "in most cases to be the result of slumping or landsliding associated with earthquakes or with wave action associated with strong storms."
Explosive decompression of underwater methane could also be a factor.
Jensenius said he is trying to gather information on the waves that hit Boothbay Harbor, adding that he has asked local businesses such as banks whether the event might have been recorded on security videos.
"It could be this or it could be that, but as a science, it is very difficult to tie it down," he said of the waves.
List also said the waves could have been triggered by the same conditions that cause a tsunami, including a breaking glacier. Rogue waves can result from a tsunami traveling through the ocean that breaks "down into numerous waves."
According to the National Weather Service, no earthquakes or seismic activity were reported in the area when the Boothbay waves appeared. List noted that there was no seismic reading when the Daytona waves struck.
Tom Lippmann, an oceanographer in the Marine Sciences Department at the University of New Hampshire, said he also suspected that the Maine wave was a squall line surge. The National Weather Service incorrectly called it a tide surge, he said.
"Tides in the Gulf of Maine are essentially driven by celestial bodies' pull on the earth's water," he said. "They're very well predicted and very well known."
Residents and business owners in Boothbay said they were glad the phenomenon didn't happen at high tide, when it might have caused massive flooding and more extensive damage. Janice Newell, who lives nearby in Head of the Harbor, told the local newspaper the rushing water "was of biblical proportion."
"There were three large whirlpools in the inner harbor, up to within a foot of my neighbor's wall," she told the Boothbay Register. "It was beautiful, but it was scary."
Elena Smith, a waitress and part-owner of McSeagull's restaurant overlooking the harbor, said the late-afternoon lunch crowd sat speechless as the waters rose and receded. She was stunned to see the normally safe and placid harbor suddenly run like rapids. Some residents reported seeing massive whirlpools of water that disappeared, leaving clam shells and seaweed in vortex patterns on the harbor floor.
"It felt like somebody took the plug out somewhere" in the ocean, Smith said. "It felt like there must have been water missing in the ocean someplace."