Extreme cold weather is driving capacity attendance at homeless shelters, causing pipes to freeze and burst and generating alerts from Environment Canada and the city of Toronto.

An extreme cold weather alert remains in effect for Toronto and much of southern and eastern Ontario after temperatures dropped to - 22 C overnight on Thursday and stayed cold on Friday morning.

As people made their way to work and school on Friday, they had to contend with outside temperatures of -23 C and - 34 C with the wind chill.

Environment Canada issued a windchill warning for the morning, but lifted the warning around 10:40 a.m.

During extreme weather alerts — times when the overnight temperatures plummet below - 15 C — more spaces are added at shelters and more ground crews are sent out overnight to reach those on the street who are at a greater risk of injury or death due to the cold.

People are asked to call 311 if they see someone in need of assistance, or 911 if it is an emergency.

Nearly 4,000 people used Toronto shelters overnight Thursday. The Salvation Army Shelter on College Street was at capacity, with each of its 124 beds filled. The shelter on Jarvis, which has 118 beds, was also full.

The city's Out of the Cold program, which works to find shelter for the city's homeless in times of extreme cold, had to spread the demand over a series of shelters.  Manager Jane Roy spent the night distributing blankets.

"There was a lot of extra people at each of our sites," he said. "And each of our sites dealt with that as well as they could and anyone who couldn't be accommodated was referred to other shelters."

Toronto paramedics took a man to hospital after he was found sleeping behind a church near Yonge and Bloor streets just before 5 a.m. He was taken to hospital and is expected to survive.

CBC's Trevor Dunn reported that he watched people dash to and from buildings in downtown Toronto on Friday morning, an apparent attempt to minimize their time out in the bone-chilling cold.

The cold caused problems and delays for the TTC as 48 streetcars were out of service due to freezing air brakes.

GO Transit also reported problems due to the weather with delays of up to one hour on the Kitchener line and delays on its Lakeshore East and Lakeshore West lines. GO has posted information about the delays here.

CBC overnight reporter Tony Smyth reported that an industrial building located at 1450 The Queensway partially filled with water after a pipe burst. The building had water up to its windows. Much of that water froze, turning the building into an "ice cube," Smyth reported.

Many Toronto residents used social media to report hearing strange booming noises in the night. CBC meteorologist Jay Scotland reported that they may have been hearing a  "frost quake," a noise caused when freezing water expands underground.

For those tired of the extreme cold, some relief is on the way. Temperatures are expected to rise significantly on Saturday, with highs of -1 C in the forecast.

What to wear

According to Environment Canada, exposed skin will only take about 10 minutes to freeze in these temperatures, so bundling up to avoid frostbite is extremely important if you have to go outside.

CBC’s Trevor Dunn went to retailer Mountain Equipment Co-op, specializing in how to handle any sort outdoor activity in any weather, to see the best ways to keep safe and warm when outside.

“We recommend a layering system,” said Cameron Dempster, Outreach Coordinator at MEC.

He says starting with underwear and modified versions of long johns is the first step,

“Polartech, powerdry, a lot of fancy words but these are old-fashioned long underwear,” Dempster said. “Not quite old-fashioned, these do have some great technologies that are going to help keep sweat and moisture away from the body so you’re not cool and damp on a day like today.”

Dempster says that a pair of fleece pants and a fleece zip-up with a gortex jacket to block the wind would also greatly help.

And on a day like today, one pair of gloves might not be enough either.