Bernie Sanders surged to victory in the Colorado caucus, giving him some breathing room to continue his battle with Hillary Clinton even as the Democratic front-runner won more of Super Tuesday’s delegate-rich contests.

At 1:10 a.m., the Vermont senator led the former secretary of state by nearly 59 percent to 40 percent, with 98 percent of precincts reporting.

Democrats showed up in larger-than-expected numbers across the metro area and other parts of Colorado on Tuesday for caucuses that featured the state’s only straw poll for president. Republicans opted not to have a statewide presidential poll at their caucuses.

Sanders fought hard for Colorado, organizing several rallies and making other appearances since last year. He was rewarded with a broad-based victory in most of the state’s regions.

“It shows his advantage, in particular, in caucus states,” said Seth Masket, chairman of the University of Denver’s department of political science. “Caucuses are a good environment for a candidate like Sanders, who draws younger, enthusiastic voters — particularly those who see themselves as part of a movement.”

Voters such as Adam Davis, 21, who voted at Denver’s East High School.

“I’ll stand in the rain if I have to for Bernie Sanders,” he said.

On the biggest night so far of the Democratic nomination contest, Clinton won seven state primaries, mostly in the South, where Sanders has struggled to attract African-American voters. Her seventh projected win was Massachusetts.

Sanders won in four states, also including the Minnesota caucuses and the primaries in Oklahoma and Vermont.

“The math still overall looks pretty good for Clinton, but Sanders overall had a pretty decent showing for the night,” Masket said. “So he certainly has a rationale to continue fighting.”

In Colorado, Sanders was leading by nearly 10 percentage points in Denver and by much greater margins in every other congressional district statewide except one. In the 6th Congressional District, which includes some of the city’s south, east and north suburbs, Clinton had led by nearly 4 percentage points in earlier results, but by midnight, Sanders had flipped the margin and was leading there, too, by nearly 4 points.

PREFERENCE POLLS: Complete Democratic caucus results Mobile users: See results here

Unlike most other contests Tuesday, Colorado’s caucuses offered more difficult-to-read results, with delegate apportionments to Sanders and Clinton still unclear.

The results will provide only a projection of the eventual winner of Colorado’s 66 delegates to the Democratic National Convention. Those will be selected at meetings up through the party’s April 15 state convention. The state has an additional 12 superdelegates who decide their support independently, with most already backing Clinton.

The final settling of most delegates will occur based on congressional district-based math that determines 43 of the delegates.

Colorado Democrats’ heavy turnout meant that at megasites including East and North high schools in Denver, lines stretched around the block and caucuses began late or were starting while voters still waited to get in. The party organized 3,010 precinct caucuses at more than 400 locations around the state.

It appeared the turnout could approach the 120,000 who caucused for Democrats in 2008.

Some caucus site coordinators were forced to improvise. At East High and at a site in Fort Collins, that meant moving some caucuses outside, in the latter case apparently by order of the fire marshal.

Democrats also faced some complaints of disorganization. At Denver’s Byers Middle School, where one reader reported that officials still were reading caucus rules and directing people to rooms more than an hour after the scheduled 7 p.m. start.

At Longmont’s Mountain View Elementary, where some voters waited in line outside until after 8 p.m., amid worries they might be turned away, Mike Metlay arrived early with his wife to caucus. He didn’t plan to volunteer. But he saw how busy it was, with an estimated 3,000 people inside by 7:30 p.m., and “I grabbed a clipboard to help.”

After Sanders gave a victory speech in Vermont, where he won his home state’s primary, and while Clinton spoke in Miami about her wins, Colorado Democrats caucused away from the candidates’ glares.

David Cleland was one of the first people at Denver’s North High. He had attended his first caucus eight years ago, and this time he said he planned to vote for Sanders. “He is saying a lot of the right things to make changes in health care and the education system (that) I’m not hearing Hillary saying,” Cleland said.

Sheila Davis, a Clinton supporter at North, acknowledged Sanders’ appeal among the heavy number of young supporters from the 10 precincts that caucused there.

She said she just thinks Clinton would make a better president.

“I love Bernie, but I think Hillary is more prepared,” Davis said. “I don’t see how he could get anything from Congress.”

Inside East High, where 18 precincts were expected to draw an estimated 6,000 Democrats, one precinct chairman, David Scarborough, stood on a chair and read the 12-step agenda in the gym.

“I’m blown away this many of my neighbors showed up,” he said, passing a “buck bag” to help pay the cost of caucusing.

He asked caucuses to raise hands to show support for local candidates. And for the presidential preference poll, people divided into two sides to show their support. The Sanders side appeared at least twice the size of the Clinton cluster. In one straw poll, he led Clinton 97 votes to 41.

As of a week ago, Sanders had spent more than twice as much as Clinton on TV ads in Colorado leading up to the caucuses.

“If Sanders is going to stay in the game, he needs to point to (victories in) three, four or five states” on Tuesday night, Denver political analyst Eric Sondermann said before the caucuses began.

Sanders pulled that off Tuesday, with Colorado’s help.

Staff writer Jenn Fields contributed to this story.