enlarge Doug Jones/Staff Photographer

Sam Spaulding, a deckhand for Casco Bay Lines, stays bundled up as he throws the dock lines for the arrival of the ferry in Portland from Peaks Island on Wednesday.

enlarge Gordon Chibroski/Staff Photographer

Scott Moulton of South Portland’s Parks and Recreation Department works with a crew Wednesday to put a new coat of ice on the skating pond at Mill Creek Park. Arctic air is putting a big chill on Maine and is expected to last until next week.

COLD-WEATHER TIPS

AT HOME: Have alternative heat sources in case of power failure. Also have emergency supplies, such as bottled water, blankets, matches, a fire extinguisher, a first aid kit, a flashlight, a battery-operated radio and a non-electric can opener. Stuff towels under doors. Cover windows at night. Avoid caffeine and alcohol – they cause loss of body heat.

IN THE CAR: Have blankets, a first aid kit, a windshield scraper, booster cables, a cell phone, a tool kit, bottled water, canned or dried foods, a can opener, a flashlight and extra batteries, and a bright cloth to tie to an antenna or door handle.

WATER PIPES: Insulate those running along exterior walls. Let faucets drip, and open cabinets under sinks to allow heat to get to pipes.

PETS: Don't leave them outdoors.

SPACE HEATERS: Don't operate near flammable materials, avoid using extension cords. Have a battery-operated carbon monoxide detector and don't use generators, grills, or camp stoves inside.

CLOTHING: Outdoors, wear a hat, a scarf or a knit mask, sleeves that are snug at the wrist, water-resistent coats and mittens (warmer than gloves). Dress in layers. The outside layer should be wind-resistent.

Source: Centers for Disease Control and Prevention

GREATER PORTLAND TEMPS

TODAY

HIGHS: 10-15

LOW: Minus 5

WIND CHILL: Minus 29

FRIDAY

HIGH: 12

LOW: Minus 4

SATURDAY

HIGH: Around 15

LOW: Minus 5

SUNDAY THROUGH TUESDAY

HIGHS: Mid to upper 20s.

LOWS: Around 10

Source: National Weather Service

SOUTH PORTLAND — Jim Pellegrini has a pretty straightforward approach to deciding whether it's too cold to work outdoors building homes.

"We get up in the morning and if it feels cold, we stay home," Pellegrini joked as he, Glenn Childs and Dana Crocker worked on the frame of a house they're building on Route 77 along the Cape Elizabeth line.

Childs, co-owner of J&G Builders, conceded that it's not really that simple.

"You're self-employed. You want to make money, you work," he said, "but if you're cold, you're not going to be productive."

Childs said he and the other two expect to be at home Friday, when temperatures will likely be below zero when he starts his workday at 7:30 a.m.

Maine is about to be hit with the coldest temperatures so far this season, with lows expected to dip below zero and highs expected just above that mark today and Friday. The cold snap is expected to last at least a week because of a dip in the jet stream that is allowing cold air from Canada and the Arctic to sink south.

The jet stream, though, doesn't have any effect on whether certain people work outdoors. That group includes Nick Ferrara, a deckhand for Casco Bay Lines.

Ferrara said there's really no way to avoid working outside while handling the ferry boats' lines, loading cargo and taking passengers' tickets. En route to the islands, he said, the deckhands can usually stay inside unless they need to shovel snow off a boat's decks, so they're usually outside for only about 15 minutes on every round-trip.

Ferrara, who has worked on the ferry line for three years, knows all the precautions to take when it's bitterly cold. He wears four layers of clothes and two sets of gloves.

Another ferry-line worker, maintenance man Lloyd Jones, said he wears a T-shirt, long underwear, a shirt and a fleece. When he has to go outside, he adds a jacket, and he uses hand warmers and keeps his gloves on when he can.

Jones, who has worked on commercial fishing boats, said winters have actually been milder the past few years.

He remembers when ice chunks would move up the Fore River with the tide and get jammed together. It was possible to walk across them from Portland to South Portland.

Lately, "we've been on a little streak of the mildest winters I've seen in a while," Jones said. "And I'm not complaining."

Diane Frederickson said she'd like to keep her job as a toll collector, but she wishes the geography was different.

"I'm used to this cold, but we do wish we were at Florida tolls," said Frederickson, who works at the Gardiner tollbooths for the Maine Turnpike Authority.

Although the tollbooths have heaters, Frederickson said they're no match for temperatures near zero when a booth's window has to be opened over and over.

"I wear a lot of layers. I can hardly move," she said.

Frederickson said her hands and face bear the brunt of the cold, and she tries to keep her fingers warm between collecting tolls by holding her hands in front of a small heater blowing warm air.

Still, "it's a very busy toll, and our hands get cold."

Frederickson should be alert for numbness in her hands and a loss of the skin's normal pinkish hue, said Mike Baumann, medical director of the Maine Medical Center Emergency Department. Those are warning signs for frostbite.

Baumann said it doesn't take much exposure, when the air temperature dips into single numbers, for frostbite to set in. If the skin gets numb and loses its color, it's time to go indoors or cover up any exposed skin, he said.

The best way to ward off frostbite is to splash warm water on the skin, Baumann said, but he said to be careful – the numbness means that it's easy to inadvertently burn that tender skin with water that's too hot.

Most at risk for frostbite, he said, are parts of the body away from the core, such as fingers, toes and the tip of one's...