The brutish storm has grown swiftly into what could be one of the panhandle's worst hurricanes in memory, with destructive winds, up to 30 centimetres of rain and a storm surge of up to four metres.

According to Environment Canada, the potent weather system is expected to weaken into a tropical storm after making landfall in Florida and is forecast to track south of Nova Scotia on Friday.

The forecaster's long-range models are calling for the possibility of heavy rainfall in parts of Nova Scotia, depending on how close the system comes to the province.

At midday, the hurricane was closing in on the Florida panhandle with potentially catastrophic winds of 233 kilometres per hour, making it the most powerful storm on record to menace the stretch of fishing towns, military bases and spring-break beaches.

"I really fear for what things are going to look like there tomorrow at this time," Colorado State University hurricane expert Phil Klotzbach said in an email.

The storm quickly sprang from a weekend tropical depression, reaching Category 4 early Wednesday as it drew energy from the Gulf of Mexico's warm waters. That was up from a Category 2 Tuesday afternoon.

"The time to evacuate has come and gone ... SEEK REFUGE IMMEDIATELY," Florida Gov. Rick Scott tweeted, while the sheriff in Panama City's Bay County issued a shelter-in-place order before dawn.

Rainfall could reach up to 30 centimetres and the storm surge could swell to four metres.

The storm appeared to be so powerful -- with a central pressure dropping to 933 millibars -- that it is expected to remain a hurricane as it moves over Georgia early Thursday. Forecasters said it will unleash damaging winds and rain all the way into the Carolinas, which are still recovering from hurricane Florence's epic flooding.

"We are in new territory," National Hurricane Center meteorologist Dennis Feltgen wrote on Facebook.

"The historical record, going back to 1851, finds no Category 4 hurricane ever hitting the Florida panhandle."

Several hours ahead of landfall, seawater was already lapping over the docks at Massalina Bayou near downtown Panama City, and knee-deep water was rising against buildings in St. Marks, which sits on an inlet south of Tallahassee.

Huge waves pounded the white sands of Panama City Beach, shooting frothy water all the way to the base of wooden stairs that lead to the beach.

More than 5,000 evacuees sought shelter in the capital city, which is about 40 kilometres from the coast, but is covered by live oak and pine trees that can fall and cause power outages even in smaller storms.

Only a skeleton staff remained at Tyndall Air Force Base, situated on a peninsula just south of Panama City.

Meteorologists watched in real time as a new government satellite showed the hurricane's eye tightening, surrounded by lightning that lit it up "like a Christmas tree."

Marshall Shepherd, a former president of the American Meteorological Society, called it a "life-altering event," writing on Facebook that he watched the storm's growth on satellite images with a pit in his stomach.

With files from The Associated Press

In what turned out to be Calgary’s snowiest October day in 104 years, southwest Alberta was hit with as much as 40 centimetres of snow on Tuesday, causing a mess on the roads that continued through the night.

John Archer, a spokesperson for the Ministry of Transportation, called the conditions “severe” after the QE2 Highway was temporarily shut down following a involving as many as 30 vehicles in Carstairs, Alta. Tuesday. There were several other minor collisions were also reported on Tuesday.

Travelers on Highway 1 were stranded on the roadway for more than 13 hours because of poor weather conditions. By Wednesday afternoon, both the and lanes for Highway 1, near Canmore, Alta., had reopened.

To help with snow clearing, 60 plow operators from Edmonton made the trip south and are expected to remain in Calgary until Wednesday evening. Chief Tom Sampson of the Calgary Emergency Management Agency said that measures like that don’t happen often but he was pleased with the comraderie.

“Couldn’t be a prouder day to be a city employee, the way people worked through the night to ensure that we’re ensuring better service today,” he said in a news conferenceWednesday.

Sampson added that it was “remarkable” to see how residents were lending help to neighbours.“Calgarians have been helping Calgarians dig out. It’s been remarkable. From homeowners to businesses—they’ve been doing great work,” he said.

Sampson asked residents to make sure they weren’t shoveling snow onto the street and to clearsnow from furnaces and storm drains.

Doug Morgan, a spokesperson with Calgary Transit, was proud of theturnaround from Tuesday as buses were getting around and not getting stuck by Wednesday afternoon. “Yesterday was a challenge, so we’re always looking for places to improve … and reviewing our response to this unusual weather event.”

Troy McLeod, the city’s director of roads, reminded residents to keep their cars off the street because of a 72-hour parking ban.

“We’ve had a record snowfall event … with some areas getting 45 centimetres. When in October, we normally receive 10 cm in an entire month,” he said.

as the storm appears to have shifted east, where another four centimetres of snow is expected by Wednesday night.

With files from CTV Calgary, CTV Edmonton and The Canadian Press

UPDATE (11:39pm) RCMP have released a statement.

— 511 Alberta (@511Alberta)

UPDATE : WB Hwy1 in the area of Lac des Arcs is now open. No ETO on eastbound lanes at this time. (6:21am)

— 511 Alberta (@511Alberta)

Environment Canada has issued snowfall warnings for the Cariboo, Chilcotin and 100 Mile regions, as well as Yoho and Kootenay Parks, and for mountain passes through the Shuswap, north and east Columbia.

As much as 30 centimetres could blanket the two parks and the mountain passes of southeastern B.C., while accumulations of 15 to 20 centimetres are forecast in the other areas by Tuesday.

The snowy weather arrives on the same day as winter tire regulations come into force across the province, requiring vehicles to be equipped with appropriate winter tires on specific highways across the North, Interior, South Coast, and Vancouver Island.

Drivers whose vehicles don't have tires with either the M+S or mountain/snowflake symbol could face a fine of $109 dollars.

Elsewhere, rainfall warnings remain in effect for Greater Vancouver and Howe Sound, as the weather office calls for up to 50 millimetres of rain through the day, raising the potential for localized flooding in low-lying areas.

That’s when Gatineau resident Vincent-Carl Leriche ran to peek out of his window. He saw parts of the roof of his building ripped off, wood and other debris beginning to swirl violently in front of him.

“I grabbed my camera and a few seconds later on, the tornado started to form right in front of me,” he said in an interview with CTVNews.ca Saturday.

“I was lucky because I know there were people who were close to windows and were hit by the debris. But I was lucky,” Leriche said.

He said he could hear screaming, but no one appeared to be out in the street as .

“And in less than a minute the tornado was winding down.”

Leriche, like many other residents in the Ottawa and Gatineau region, had been listening to the warnings from Environment Canada during the hours leading up to the extreme weather event.

But it was only after he witnessed the violence of the storm firsthand that he realized how he could have been seriously hurt.

“At first, you don’t see the immediate danger of the tornado because you're just taken by the spectacle of the tornado,” he said, adding that he also took several pictures before the tornado actually touched down.

“It was very dangerous because if debris or an object that would smash through the window—at 100 km/h—there could have been a very big injury.”

But that being said, the opportunity to take up footage was too hard to pass up for Leriche.

“I was inside, but if I were out on my balcony, I probably would have went back into my apartment,” he said. “But being inside gives you the false sense of security.”

Some of the aftermath of the tornado that touched down in the Gatineau-Ottawa area. (Vincent-Carl Leriche/Facebook)

After the tornado lifted, Leriche started surveying the damage the tornado caused in less than a minute.

He said he saw lots of windows smashed, cars flipped over, and trees ripped from their stumps and strewn along the street.

“I’ve never seen a tornado before. My understanding is that [it’s] one of the first times in 24 years there’s been a tornado in the Gatineau region,” Leriche, who has been living in the city for a year and a half, said. “It was very unexpected.”

Debris that covered the street after a tornado that touched down in the Gatineau-Ottawa area. (Vincent-Carl Leriche/Facebook)

“You don’t realize how dangerous it is to be by the windows when there’s such high winds,” he said, warning other would-be tornado chasers to step back from the windows when winds are that strong.

He’s thankful that his apartment wasn’t damaged and spent Friday night without power. The following morning he was told by a policeman that he would not be able to come back into his building for the time being.

Leriche said he doesn’t know when he’ll be allowed back inside his home, but for now, he’ll be staying with friends in Ottawa. He said he’s grateful to be alive.