PORTLAND, Ore. -- Governor Kate Brown declared a state of emergency in Oregon due to severe winter storm conditions after a storm that hit Portland Tuesday night and Wednesday morning left a historic amount of snow across the metro region.

Schools, businesses and most activity in the area was either halted by snow or severely curtailed as a white blanket draped Portland and surrounding communities, falling at a pace not seen in a generation.

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"As snow continues to accumulate and local authorities respond to provide core services and clear roadways, all available state resources will be made available to ensure the safety of communities throughout Oregon," said Brown. “I urge all Oregonians to follow the recommendations of local authorities, and avoid travel while ODOT crews clear roads and work to restore core services."

Mayor Ted Wheeler on Wednesday announced a state of emergency for the city of Portland, which would allow the city to request additional resources from the state and the federal government. Portland's state of emergency will be in effect until Jan. 14, according to the mayor's office.

Snow began sticking in Portland at about 5 p.m. Tuesday, and then fell at a rate of more than an inch an hour, with some areas getting 10 inches before midnight. By mid-day Wednesday, some areas saw more than 15 inches of snow. The snowfall ended by Wednesday afternoon.

It was likely the biggest snow event to hit the city in nearly three decades. The storm even has a name - Jupiter - and it's reach is widespread, from California to the Midwest.

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Treacherous roads

Semi-trucks stuck on northbound Interstate 5 at the Marquam Bridge caused a major traffic backup Wednesday night. One driver told KGW's Mike Benner she'd been stranded for hours on the freeway. ODOT urged drivers to get off the freeway at the Barbur or Terwilliger exits to avoid the gridlock.

Withe the exception of the northbound Marquam, Thursday morning commuters were treated to plowed freeways. However, a number of cars remain abandoned. Plows had to go around those vehicles.

Mayor Wheeler urged drivers to stay off the roads and to check on those in need.

ODOT announced Wednesday morning that chains were required for all vehicles on state roads, but then announced after 10 a.m. that studded tires would also work.

ODOT later said chains were not required in the Portland area, except on trucks.

TriMet announced Thursday morning that all buses and MAX trains were back on regular schedules. On Wednesday, buses were chained and limited to 25 mph. MAX had a variety of issues. A Check the status of your line at trimet.org/alerts.

Portland General Electric said crews were working around the clock until power is restores to the thousands who lost power during the storm. Latest PGE outage numbers

The city of Seattle sent several crews and 11 heavy-duty trucks down to Portland to help restore power and clear snow off the roads.

Related: Thousands without power, trees crashing down around Portland

It All Started Tuesday night...

While Tuesday's early evening commute mostly went by without a hitch, traffic hit gridlock stage on many roads after 8 p.m.

Interstate 84 was closed in both directions at about 10 p.m. from Troutdale to Hood River. The highway reopened Wednesday afternoon.

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All drivers on state highways in Portland were required to use chains or traction tires after 10:30 p.m.

Southbound Interstate 5 was at a standstill. Cars were once again stuck on Highway 26, much like they were during a snow and ice storm last month.

A bus spun out and blocked southbound Interstate 405 near the Burnside overpass.

At Portland International Airport, some flights were redirected from Portland to Seattle due to the snow. Runways were temporarily closed so plows could remove snow. Click here to see the latest on flights cancelations

The Blazers were forced to land at Seattle-Tacoma International Airport and fly into Portland Wednesday. They landed in Portland Wednesday afternoon and defeated Cleveland 102-86.

ODOT preparation

Following that December snow storm, the Oregon Department of Transportation said it would consider using salt on Portland area highways.

When it snowed last Saturday, ODOT used salt for the first time on Highway 26. Crews will use it again, if needed, but said Tuesday they still didn’t have access the salt, or a place to store it. It's unclear whether ODOT used salt Tuesday night.

“We’re working on storage. We are working on the truck dispersal of it, and we are working on what level of intensity to distribute the salt. We are not going to spread it everywhere willy-nilly, that’s a bad idea. But we are going to continue to use it, and will find our opportunities, very controlled, surgical and tactical,” said ODOT spokesman Don Hamilton.

PHOTOS: Snow in Bend | Sun rises over snowy Oregon | Storm blankets Portland | Kids in the snow | Pets in the snow | Snowmen | Storm brings down trees