Sheets of ice up to a foot thick in the Chesapeake Bay have beached small boats and fishermen, hampered operations at the port of Baltimore and kept one Coast Guard cutter busy tending to stranded islanders for more than a week amid the worst freeze in decades.
A ship designed to break ice recently gave up on carving a path through the eastern Chesapeake Bay near Rock Hall after it moved only two miles in five hours. The conditions are so treacherous, even the pilots who spend years training to guide ships up the bay can't navigate in the dark, their trusty buoys turned to icy mounds or pushed aside by floes.
Frigid weather — forecast to remain well into March — are delaying normal rites of spring, forcing the Maryland Zoo in Baltimore to close for more than a week and local reservoirs to delay the start of boating season.
While January 2014's "polar vortex" brought a freeze that hadn't been seen since the 1990s, the layer of ice atop local waterways is even larger and thicker this winter. This month is expected to be Baltimore's second-coldest February on record.
North of the Bay Bridge, more than 90 percent of the bay is ice-covered, according to the National Ice Center, which monitors ice conditions around the bay, on the Great Lakes, and in the Arctic and Antarctic.
That is significantly more than a year ago. After a frigid January last year, the Chester, Choptank, Middle and Back rivers were more than 90 percent ice-covered, while farther up the bay, the Bush River was completely iced over. But most of the rest of the upper bay was only 10 percent to 30 percent ice-covered, according to the center.
The ice has grown amid historic cold. The average temperature this month at Baltimore-Washington International Thurgood Marshall Airport is on track to be about 25 degrees — which would make it Baltimore's fourth-coldest month on record, behind only January 1977, January 1918 and February 1934.
The 1-degree low Feb. 20 at BWI was the coldest there since Jan. 19, 1997, according to the National Weather Service. Before that, it hadn't been colder since Feb. 4, 1996, when BWI reached 1 degree below zero.
Such intense and prolonged subfreezing temperatures are what's needed to build ice on brackish bodies of water like the bay, Cover said. Salty water, which freezes at 28 to 30 degrees Fahrenheit, tends to sink to the bottom of the bay because it is more dense, and it is warmer down there, away from harsh winds and frigid air at the surface, he said.
Snowfall can speed ice buildup because it adds a fresh layer of ice-cold water at the surface. About 21 inches of snow have fallen at BWI this winter, slightly more than in an average season.
The weather has kept U.S. Coast Guard and Maryland Department of Natural Resources icebreakers busy up and down the Chesapeake.
While ice-breaking is more common in the fresher waters of the upper part of the bay, the cutter Chock spent eight days this month in and near Tangier Sound, delivering food and supplies to the residents of Tangier Island, Va., and precious heating oil up the Wicomico River to Salisbury, said Chief Mike Kozloski of the Coast Guard. A normal tour for the ship is two to three days long, he said.
"The people on Tangier Island were very happy to see us," Kozloski said. "They were asking if we were coming back soon."
The Virginia National Guard also flew in food, medicine and mail to the island 14 miles from mainland Virginia.
Momentum and a steel hull can help regular ships break through the ice on their own, and major shipping channels have been kept clear without much help from cutters.
But ice can still build up and form a plug requiring the help of an icebreaker, Kozloski said. While the Chock has tended to Tangier Sound, the Coast Guard cutter James Rankin has been working to free frozen buoys in the Baltimore area and clear paths northward, including on the Maryland portion of the Chesapeake & Delaware Canal.
Two Maryland cutters, the John C. Widener and A.V. Sandusky, have been offering assistance around Annapolis and in Tangier Sound, respectively, while the J. Millard Tawes is typically posted at the channel from Crisfield to Smith Island.
But there has been more to do than they can keep up with. The morning after the Widener cleared a path in Annapolis harbor, floes an inch thick reappeared, said John Gallagher, director of hydrographic operations for the Department of Natural Resources.
"There's a lot of pent-up demand from watermen and marine interests," he said. "We're hoping the weather breaks next week."
A fresh round of snow falling atop already-icy buoys last Saturday made many look like icy bumps. Ice floes have knocked other buoys dangerously close to shore or into the middle of channels, said Capt. Eric Nielsen, president of the Association of Maryland Pilots.
That meant ships planning to travel at night to the Dundalk and Seagirt marine terminals had to anchor until morning through Wednesday, said Richard Scher, the spokesman for the Maryland Port Administration.
Doug Wolfe, vice president of Ceres Marine Terminals at the port, said the intense cold, particularly in the past month, has thrown some vessels off schedule, slowed work on the piers and "taken a toll" on equipment.
"Production is slower, so you're running your equipment longer," he said. "Your fuel charges go up."
Ceres, a terminal operator and stevedore that handles automobiles and cruise ship cargo, has two salt trucks and four plows to help clear its 17 acres, and they've been busy this winter, Wolfe said. Time is money on the piers, he said, and work rarely stops for snow and ice.
This winter has been "pretty miserable," he said. "It's surprising that the cruise ships don't leave full and come back empty."
Meanwhile, fishing and oystering has been brought nearly "to a halt," said Robert T. Brown, president of the Maryland Watermen's Association.
"Ninety-nine percent of the bay is not working now," he said. "On the whole bay [Wednesday], there were probably only three boats working."
In such frigid conditions, Brown said, it isn't hard to put a hole in a boat that doesn't have a steel hull. Heavy 40-foot boats with wooden or fiberglass hulls can be punctured by jagged 6-inch-thick ice, even when the vessels are moving slowly, he said.
Watermen around Tilghman Island described at least two rescues this month, saying they came to the aid of comrades who were close to sinking after ice tore their hulls.
For watermen who don't risk the icy waters of the bay, the winter months can still take a toll. Some have lost nearly a month's work, Brown said.
"Some parts of the bay have been frozen for the whole month of February," he said. "People don't realize the hardship that a hard winter puts on us."
The Watermen's Association has asked the Maryland Department of Natural Resources to extend rockfish and oyster seasons because of the harsh conditions, he said.
"Even with it warming up now, we've got to wait another week for the ice to clear," Brown said.
But a prolonged warm-up remains elusive. Forecasts suggest continued below-normal temperatures into the middle of March, according to the Climate Prediction Center in College Park.
Maryland Zoo officials said with walkways still icy, they expect to remain closed through at least Thursday. The regular season had been expected to begin Sunday.
Boating had been scheduled to begin Sunday at Prettyboy and Liberty reservoirs but is on hold, according to Baltimore public works officials, who maintain the reservoirs.
After a possible wintry mix Sunday night, temperatures are expected to rise into the 40s Monday. But forecasters are watching a wintry system expected to pass through the middle of next week.
Baltimore Sun reporters Colin Campbell, Kevin Rector and Catherine Rentz and librarian Paul McCardell contributed to this article.