The state of emergency will include a 24-hour-a-day, weeklong parking ban on all streets south of Union Street, starting Tuesday at noon, to allow for snow removal.
City council made the declaration during its regularly scheduled meeting Monday night in the midst of a blizzard after Kevin Clifford, the head of the Emergency Measures Organization and fire chief, advised there are some streets that are inaccessible to emergency vehicles.
A total of 96 centimetres of snow is already on the ground, with up to 40 centimetres more on the way, according to Environment Canada.
Clifford recommended the state of emergency to "get us back to a stable environment."
Earlier in the day, Saint John police warned motorists about how high snowbanks are reducing the ability to see pedestrians and other cars.
It is the first time a state of emergency has been declared in the south-central peninsula because of snow, said Clifford.
The last state of emergency in the area was in 1986, he said, when an underground gasoline leak from an Irving gas station at King's Square got into the sewer system and caused a series of explosions, destroying a restaurant and damaging three other businesses.
Under the parking ban, any vehicles left parked on streets in the affected area will be towed, city officials said.
The business district will be cleared first, said Mayor Mel Norton. "Streets will be reopened for regular parking as cleared," he tweeted.
The city is asking area residents to move their vehicles off-street as soon as possible, but the parking lots normally used during overnight snow parking bans will not be available during the day, officials advised. Regular paid parking patrons use those lots during business hours.
Free parking will be provided at the Peel Plaza garage, starting Tuesday morning, for those with south-end parking passes, and Saint John Transit will establish some temporary bus routes to shuttle people to their streets.
The state of emergency comes after a major fire in the uptown Sunday levelled a building containing a ground-floor business and upstairs apartments, gutted an adjoining house, and extensively damaged the exterior of a third building, while water used to fight the fire flooded the electrical panel of an apartment building across the street, temporarily displacing more than 100 tenants.
Blizzard wreaks havoc on roads
Across New Brunswick, police are advising motorists to drive with caution and avoid any unnecessary travel, with much of the province under a blizzard warning.
Heavy snow is leaving roads snow-packed and strong winds are limiting visibility.
An intensifying low-pressure system approaching the region tonight will cross Nova Scotia Tuesday morning, says Environment Canada.
Snow, at times heavy, will spread from southern New Brunswick across the remainder of the province this evening.
Total snowfall amounts will range from 10 to 20 centimetres over northeastern New Brunswick to 30 to 40 centimetres over southeastern sections of the province, according to the weather agency.
The snow will combine with increasing northeast winds to created blowing and drifting snow and near-zero visibility at times.
'Here we go again'
"Here we go again! Road conditions have deteriorated," the Saint John Police Force tweeted. "Please slow down and keep room between you and the car in front of you."
All Saint John Transit buses were pulled off the roads at about 6 p.m., shortly after one of the buses skidded and took out a lamppost on King's Square north.
The City of Moncton also stopped all Codiac Transpo buses between 6 and 6:30 p.m. Service is scheduled to resume at 9 a.m.
"Roads are terrible. Slow down and drive safe," the Kennebecasis Regional Police Force traffic unit posted on Twitter.
"In the midst of another storm, travel safely today. Adjust your speeds, and drive with caution," advised Fredericton police.
The blizzard also affected air travel, with several flights in and out of the Saint John, Moncton and Fredericton airports either cancelled or delayed.
Extreme cold warning
An extreme cold weather warning has been issued for parts of the province, including Campbellton and Restigouche County, Edmundston and Madawaska County, and Grand Falls and Victoria County.
The nor'easter's strong northwesterly winds and bitter cold air have combined to give wind chill values between –35 and –39, according to Environment Canada.
In northern New Brunswick Monday night will be windy with snow, heavy at times, and blowing snow tapering to flurries by morning. Snowfall amounts of 10 centimetres in the west and 20 to 30 centimetres in the east and a low of –22 C.
Overnight for Fredericton and area, it will be windy with snow, heavy at times, and blowing snow bringing 20 to 30 centimetres and winds gusting to 60 km/h.
For southern New Brunswick, it will be windy with snow, heavy at times, and blowing snow becoming mixed with ice pellets near or after midnight.
Snowfall amounts of up to 40 centimetres are expected with winds gusting to 80 km/h overnight.
CBC meteorologist Peter Coade says a ridge of high pressure will move across the Maritimes late on Tuesday, bringing a short stretch of fair weather.
"Another disturbance will swing into the region later on Wednesday with some snow and/or rain for Thursday. As you can imagine, temperatures will be on another roller-coaster this week," he said.
NB Power records peak
NB Power issued a graphic on Monday morning showing its energy use peaked at 3,030 megawatts today.
The power utility said New Brunswick's grid hits its peak on weekdays between 6 a.m. and 9 a.m., when people turn on their electric heaters, hot water and other devices at the same time.
NB Power is running a contest intended to encourage power users to reduce the amount of electricity they use during peak hours.