A driver who had expected to cross the Potomac River found the White’s Ferry closed earlier this week due to icy conditions on the water. (Michael S. Williamson/Washington Post)

You can’t fight fire with ice. That’s a frozen fact that public safety officials are grappling with as extreme cold continues to grip much of the country this week. Broken water mains make fire hydrants weak. The water that firefighters carry on their trucks can freeze. Pumps lock up. Firefighters fall down.

“You see people trip on hose lines during sunny days, much less add ice, too,” said Northern Virginia firefighter Chris Kamienski at Arlington, Virginia’s Station 1 Wednesday.

Plumbers have their own low-temp truisms (pipes burst), as do drivers (batteries fail), engineers (metal breaks) and doctors (joints ache from cold, bones crack from falls). It’s all the toll of the cold. When the air gets down near zero, parts fail and people despair. From freight rails to frost bite, a deep freeze can mean deep trouble for a city – and a species – built to operate at more temperate temperatures.

Meteorology has become a doomsday science. Bomb cyclone? Polar vortex? What happened to scattered flurries?

“When things get very cold, things change,” John Jarrell, president of Materials Science Associates in Rhode Island. “The nature of materials change, and the systems we’ve designed to operate at normal temperatures are stressed.”

The evidence is everywhere. Crews are struggling to keep up with a record number of fractured water mains, with almost 80 reported in the Maryland suburbs Wednesday. DC Water was working to fix 50 others while fielding more than 200 emergency calls a day tied to the frigid temperatures. Plumbers reported hundreds of calls for broken pipes at homes, apartments and office buildings, including a burst hot water supply line that spawned a small sidewalk glacier in downtown Washington.

More than 5,000 motorists in the District of Columbia, Maryland and Virginia called for help Tuesday, mostly for dead batteries, flat tires and getting locked out of their vehicles, probably from leaving keys in their cars while warming them up, according to AAA Mid-Atlantic.

The cold played its winter wiles on bodies too. Sometimes the bodies were complicit, such as the young people in Loudoun County, Virginia, who found themselves in hypothermic waters earlier this week after driving their SUV on the ice, or the skater who broke her wrist on the frozen C&O Canal.

But some bystanders were also felled by the freeze. Joints, particularly arthritic ones, grow achy in the extreme cold, possibly because the low barometric pressure causes tissues to swell. Sufferers of cold urticaria disorder have an itchy allergic reaction to cold air, and Raynaud’s disease causes fingers and toes to go numb at times like these.

It was a remarkable bill of physical breakdown and cracked routines in a week without significant snow or high winds. It was pure cold air snapping bits off the built environment, even before the bomb cyclone detonated in the form of a monster winter storm forecast for Thursday. This winter, still in its infancy, was already wearing on the local spirit.

“I am so tired of being cold – already!,” lamented Julie Ann Pixler, a former C-SPAN producer, on The Post’s Facebook page.

“Same,” seconded reader Arielle K. Masters.

The main cold weather culprits, according to Jarrell, are the facts of physics. Extreme cold causes most materials – such as plastic pipes and metal parts – to become less flexible and more brittle. If your Metro car has to single track around a cracked rail – like the one in D.C. Wednesday evening – you can impress your fellow passengers by blaming the dreaded “ductile to brittle transition.”

Water, on the other hand, swells when it freezes, forming a perfect pipe-breaking scenario, especially when the temperatures are cold enough to penetrate deep into the ground where the usually snug pipes are buried.

Chemical reactions, meanwhile, tend to slow in the cold, weakening car batteries. Oil becomes thicker and frozen metal parts shrink at different rates – think about aluminum pistons sitting in tight iron cylinders – making engines harder to budge for those already feeble batteries. Nothing is quite normal.

Think of a Milky Way bar, Jarrell suggests. Break it in two at room temperature and its various layers will stretch and ooze at different delicious viscosities. But pull it from the freezer and “you can snap it like a candy cane,” said Jarrell. “At low temperatures, things begin to act in ways contrary to what we’re used to.”

Kamienski, along with firefighters across the D.C. region, know how tricky it gets with winter and water. He points to the “pump shift” knob below the steering wheel of Engine 101, the controls he’ll use to keep the water moving through the truck’s 750-gallon tank and 30-gallon pump in order to keep it fluid. Elsewhere, the truck’s cold weather kit includes a plastic sled to pull injured people over frozen ground, snow shovels and cat litter to spread over slippery patches.

Ice can lock their extension ladders up. Frozen hoses refuse to coil. But the calls keep coming. An overhead screen flashed the details of a medical call. In his rush to respond, Kamienski almost left his new insulated Yeti mug behind.

“Don’t want to forget my Christmas gift,” he said.

Dock hand Melvin Castellon works with others to break up ice around a dock at the Washington Sailing Marina. (Matt McClain/Washington Post)

At the Washington Aqueduct, workers battled the freezing Potomac by hand, like ancient whalers, using steel rods to punch through ice two inches thick near the intake pipes that supply the District of Columbia and parts of Northern Virginia with drinking water.

Crews had scrambled to break up the bergs Sunday after ice began to block the pipes and the reservoir level dropped, said Thomas Jacobus, the aqueduct’s general manager. “Ice eater” machines churned the water with propellers to keep more ice from forming, he said.

By Wednesday, with even colder temperatures forecast, the aquaduct had a crane and wrecking ball standing by to break up large chunks that could overwhelm the intake.

Jacobus said aqueduct officials couldn’t remember another stretch when night temperatures dipped into the single digits and daytime temperatures didn’t reach above freezing. “This is what you expect in Iowa for goodness sakes,” Jacobus said. “Nothing has a chance to warm up to defrost itself.”

Workers have wrapped black plastic around equipment to try to trap in heat and brought in portable heaters to keep smaller pipes from freezing. The extreme cold also makes chemical reactions in the water-treatment process sluggish. Crews are adding more coagulants to get dirt to settle and keeping an eye on chlorine levels to make sure the chlorine has enough time to kill bacteria.

“Our systems are taxed,” Jacobus said. “We’ll be okay, but we are right at the edge of the capabilities of our heating systems. They’re not built for this.”

And neither are we.

The Washington Post’s Katie Shaver, Luz Lazo, Debbie Truong, Perry Stein, Lori Aratani, Michael Ruane and Dana Hedgpeth contributed to this report.