As the Twin Cities prepare for what could be one of the largest snowstorms to hit the area in years, the mayors of St. Paul and Minneapolis have declared snow emergencies and are asking residents to move their vehicles off streets as soon as possible.

Both cities declared snow emergencies effective at 9 p.m. Sunday but asked residents to begin moving vehicles Saturday, the mayors announced in a joint news conference Saturday afternoon in St. Paul.

“Because the forecast calls for an extreme amount of snow, please move your vehicles off night plow routes this evening if you can,” Mayor Koahly Her said. “Moving now will help you avoid becoming stuck in a snowbank, and will give our crews room to work, and make sure you have safe roads to drive on when the time comes.”

City staff at both cities have been “working tirelessly” for the past few days in preparation of the storms, Her said, which if predictions are correct, will be a historic amount of snowfall. Crews have been treating streets to prepare for the snow, she said.

To make it easier for residents to move their vehicles, both cities are offering thousands of free parking spots.

In St. Paul, the city will open the Block 19 Municipal Ramp at Jackson and E. 7th streets in downtown St. Paul for free parking. In addition, as park and recreation lots are plowed, they will also be opened for free parking, Her said. She said residents should check stpaul.gov/snow for updated information.

The mayor also warned that city snow plows will make two passes so even if it looks like plows have been on a street, they may be coming back, she said, so residents should be aware of that before returning vehicles to snow emergency routes.

“Over the past month, Minnesotans have shown again and again how we look out for each other,” Her said. “I ask you now to check on your neighbors and those who may need help. Follow the posted parking rules, and stay off the roads unless travel is essential. This is spring in Minnesota. We’re prepared and ready to respond.”

Mayor Jacob Frey said his city is doing the same.

“The real reason we call a snow emergency is so we can get the plows through,” he said. “We recognize that this may be a very significant snow event. Our snowplow drivers are in the starting blocks and they’re ready to go. For them, this is the Super Bowl. They’ve been preparing for this kind of snow event all year. And I can tell you we’re going to have every single one of them out.”

Sean Kershaw, St. Paul director of public works, said Saturday he had just received an update from the National Weather service and that the forecast continued to call for 12 to 18 inches of snow beginning Saturday night.

“It’s going to be really heavy falling at about two inches an hour overnight,” he said. “That’s a lot of snow. We could get eight inches overnight. Following the heavy snow, tomorrow, the winds will pick up, and there’ll be strong winds that declare a blizzard warning for the whole region. After that, it will get cold … We will begin plowing the streets as soon as it starts snowing. We will be out all night. We will be out all tomorrow.”

Kershaw asked for people to stay off the roads after midnight Saturday and to have vehicles moved off snow emergency routes Saturday evening.

Cars that park in the free lots won’t have to be moved until 5 p.m. Monday, he said. He advised people to check the city websites for updated information.

The city of St. Paul will not have garbage or recycling pickup on Monday, he said, and people who have pick up on Mondays should put their bins out Tuesday morning.

Tim Sexton, public works director in Minneapolis, said the amount of snow predicted from this storm might be one of the top five snow events in history.

“Remember the Dome Buster event from 2010, where the Metrodome collapsed?” he said. “That was about 17 inches of snow. So more than that is forecast, and this is late season, heavy, wet snow. So it’s going to be inconvenient. There is no way around that. But just recognize this could be a historical event.”