(UPDATE Thursday 1:45 PM: Xcel Energy has told customers they can return their thermostats to normal. You can find our current, updated story about the cold wave in Minnesota here.)

The brutal cold gripping Minnesota made itself felt in tens of thousands of living rooms Wednesday as Xcel Energy resorted to asking customers to turn their thermostats down to 63 degrees to conserve natural gas.

The request to Xcel's more than 400,000 customers came as the utility strained in the sub-zero temperatures to keep up with heating demand.

And a few Minnesotans dealt with the nightmare of having no heat at all.

About 150 homes in the Princeton area, about an hour north of Minneapolis, lost natural gas service about 10:30 p.m. Tuesday. In response, Xcel asked about 12,000 customers in nearby Becker, Big Lake, Chisago City, Lindstrom, Princeton and Isanti to turn down their thermostats to 60.

Later in the day, the company expanded that request to all of its 460,000 gas customers in Minnesota, although Xcel expected to keep the advisory in place only until Thursday.

The heating issues weren't the only challenge posed by the once-in-a-generation chill, as Minnesotans also suffered new frostbite cases, broken water lines and transportation breakdowns.

In the Princeton area, police and fire officials went door-to-door to inform residents about the gas shut-off and that Xcel would put them up in nearby hotels. About two-thirds of those affected by the outage accepted the offer, said company spokesman John Marshall.

According to the Sherburne County sheriff, Xcel also distributed heaters.

Jason Camarena woke up Wednesday morning to find his natural gas service was out and the temperature in his Princeton home had dropped to 54 degrees. He and his wife and two children headed to the nearby AmericInn, but took it all in stride.

"How can you be mad?" Camarena said, noting that Xcel power crews had been out in the bitter cold since 3 a.m.

"I mean they have that, and we have this," he said, gesturing toward the pool where his children were swimming. To show his appreciation, Camarena brought coffee and hot chocolate Wednesday to the crews at work on the outage near his home.

Greg Butler got the temperature in his home up to 60 degrees with the help of six space heaters.

"I feel like we'll be all right," he said.

While Xcel works to restore the heat, the company enlisted the help of licensed plumbers to keep residential pipes from freezing.

"The unprecedented cold and wind that we're dealing with in Minnesota has customers running their heat almost nonstop which really increases demand on our system," Xcel said in a statement. "Because we've had some outages due to this in central Minnesota, we're taking further steps and exercising an abundance of caution to help conserve natural gas so the system can continue to operate well throughout the state."

An engineer with the Minnesota Office of Pipeline Safety is in Princeton working with Xcel to ensure that the company follows proper procedures to restore gas service to customers, Jen Longaecker, a department spokeswoman, said in an e-mail.

CenterPoint Energy, the largest gas utility in Minnesota with nearly 870,000 customers, has not had any major problems, said company spokeswoman Alicia Dixon. "We are not experiencing any low-pressure issues on our system and are not issuing any calls for conservation."

Breaking down

Meanwhile, the toll from the lingering deep freeze continued to mount. Water pipes burst and cars got stuck with dead batteries and flat tires.

Some schools, including those in Minneapolis, St. Paul, Anoka-Hennepin, Rosemount-Apple Valley-Eagan, Robbinsdale and Duluth, will remain closed Thursday.

Minnesota hunkered down Wednesday as temperatures bottomed out at 28 below in the Twin Cities and negative 30s and 40s in northern Minnesota. When the wind was factored in, the windchill made it feel like 50 to 66 below, depending on where you were in the state.

The dangerous cold sent dozens to local hospitals. Hennepin Healthcare (HCMC) in Minneapolis has treated 22 patients for frostbite since Friday, including 13 admitted to the hospital, said HCMC spokeswoman Christine Hill. The hospital also has treated numerous other people for cold-related injuries, she added.

Regions Hospital in St. Paul said it has treated 15 cases of frostbite, including some patients who had to be admitted to its burn center.

Meanwhile, the cold has put a crimp in blood donations, leaving just a one-day supply of many blood types, Memorial Blood Centers reported Wednesday.

The organization cancelled its blood drives on Wednesday and many community blood drives this week were also cancelled or postponed, said Larry Silber, Memorial Blood Center spokesman.

"No one here can remember when we had to cancel drives because of the weather," he said.

Although the organization's 10 donor centers remained opened, many donors stayed home rather than venture out in the cold, Silber said.

He is hopeful that the organization will get a bump in donations Friday and Saturday when temperatures jump above zero.

Others in Minnesota were mopping up after pipes burst overnight.

When a heating mechanism failed in a White Bear Township water tower, freezing water caused a burst and more than 100,000 gallons of water leaked from the tower's base, said Patrick Christopherson, the township's clerk and treasurer.

"No one's water use or water pressure was affected because we caught it before the water all drained out," he said.

But about 4 to 6 inches of water that flooded Birch Knoll Drive created an instant skating rink a block long, he said. A garage door on one home that backs up to the water tower was frozen shut.

Crews spent most of the day repairing the heating mechanism and scraping the street of ice, Christopherson said.

In St. Paul, Park Square Theatre employees came to work Wednesday morning in the Hamm Building to find water raining down from the ceiling in the scene shop and seeping down into the dressing and green rooms and tech offices below, said executive director Michael-jon Pease. A couple other pipes on the second and third floors also burst, he said.

When the theater staff inspected the dressing rooms and tech offices in the basement, they discovered that the sewer pipes also froze and sewage had backed up, Pease said.

"So we were a tier-three biohazard for the most of the day," he added with a laugh.

The set pieces for its upcoming "The Skin of Our Teeth" performance that begins Feb. 7 will have to be rebuilt and painted but should be ready for the start of its run, Pease said. The theater's spaces in the basement likely won't be cleaned up and repaired until later, he added.

Keeping warm

Outreach workers in the Twin Cities continued to scramble to provide warm clothing to homeless people and direct them to warming stations. Though several shelters said they would remain open around the clock, advocates say the system is not sufficient to house everyone who needs it.

"We're always in a crisis," said John Tribbett, street outreach program manager at St. Stephen's Human Services, a nonprofit serving vulnerable and homeless adults. But efforts "kicked into overdrive" this week when temperatures plunged below zero, which could be fatal for those on the street.

A biannual report conducted by St. Stephen's and the Hennepin County Office to End Homelessness last July estimated there were between 400 and 532 homeless people sleeping outside of shelters — most of whom spend their nights at transit stops or on light-rail trains.

Each winter, a number of those people lose fingers, toes and ears due to exposure, Tribbett said. During daily welfare checks at known encampments, his team ensures people have survived the night. This week, they found a man in a wheelchair sleeping at a bus station.

At First Covenant Shelter, workers have put down additional sleeping mats so they don't have to turn people away.

As dusk fell Wednesday, around 60 people sought refuge inside its warm basement to sleep or converse as volunteers cooked a batch of chili.

"This place is a godsend," said 33-year-old Bernadette Charlton, who hasn't had permanent housing for over a year. Charlton and her husband, Otis Edwards, say they've been hopping from place to place — sleeping in cars, garages and apartment complex hallways. "This is the hardest winter I've ever experienced," she said.

Staff writers Liz Sawyer and Paul Walsh contributed to this report.