Bernie Sanders delivered on his strong polls in New Hampshire, and though he faces big challenges ahead in Nevada and South Carolina there is new evidence to suggest he could ride a wave of momentum and grassroots support through these difficult, Hillary Clinton-leaning states.

Recent polling suggests that voters of all demographics — including those dominated by Clinton so far — are moving toward Sanders in recent days. This could be key if he aims to pull off upsets, or even better-than-expected performances in these states to fuel his upset bid.

After suffering a razor-thin loss to Clinton in the Iowa caucus, Sanders responded with a resounding victory in New Hampshire. The win gives his campaign a bit of wind behind their sails as they head toward what will be the most difficult test yet, the Nevada caucus followed by the South Carolina primary.

Iowa and New Hampshire were two states that leaned toward Sanders demographically, and FiveThirtyEight noted that it gets much harder from here.

“Polling has indicated that Sanders trails among nonwhite voters by nearly 40 percentage points nationally. Although no reliable recent polling is available in Nevada, Clinton leads by 30 percentage points in both of our South Carolina forecasts. In the latest Marist College poll, she’s buoyed by a 74 percent to 17 percent lead among black voters. Sanders must cut into that margin if he wants to have any chance in South Carolina or anywhere in the South.”

There could already be good signs for Bernie Sanders moving forward. Jeff Weaver, Sanders’ campaign manager, said their internal polling shows that Sanders is starting to win over voters of all backgrounds, especially younger, non-white voters.

“Younger voters are clearly the strongest group for Senator Sanders, and this is sort of reminiscent of the Obama campaign — where younger voters were the president’s strongest bloc as well — across racial lines,” Weaver said, via the Washington Post.

There could be more room for Bernie Sanders to climb in the polls as voters get to know him better. CNN columnist Julian Zelizer noted that Sanders “speaks to many middle-class Americans who don’t feel that their future is secure and who are struggling every day to make sure that they don’t fall on the wrong side of the growing economic divide.” As voters in Nevada and South Carolina — and the states that follow — learn more about Sanders, his poll numbers are expected to rise.

As Zelizer noted, Sanders has crafted a campaign message that has appeal well beyond the Democrats’ liberal base.

“Sanders promises that as president he would double down on programs that benefit the middle class. He would fight for government policies that create incentives for job growth here in the United States and programs that help to elevate the economic health of working Americans, including progressive tax policies and a robust public works program to build the nation’s infrastructure while giving people work. He has proposed raising the minimum wage to $15 an hour.”

#BernieSandersBrigade joins 100s of volunteers in Nevada, a key state for the grassroots campaign. @BernieSanderspic.twitter.com/EJXiSeWWGj — BernieSandersBrigade (@BSandersBrigade) February 6, 2016

Bernie Sanders has some other momentum in his favor. After his New Hampshire primary win, supporters took to the internet to fill the Senator’s coffers with donations. In just about 24 hours from the time polls closed until the next evening, Sanders hauled in $6.5 million, close to double the campaign’s previous 24-hour total.

Sanders raised $20 million in January alone, money that will be critical for Sanders who will be buying ads across Nevada and South Carolina.

“I’m going to hold a fundraiser right here, right now, across America,” Sanders told supporters after Tuesday’s win. “Please help us raise the funds we need — whether it’s 10 bucks, 20 bucks, or 50 bucks. Help us raise the money we need to take the fight to Nevada, South Carolina, and the states on Super Tuesday.”

While Hillary Clinton may have some big donors and super PACs in her corner, Bernie Sanders has an advantage in his small donor base. His campaign received 2.5 million donations from more than 1 million separate donors in 2015, a base that could be key if he is to take on Hillary Clinton for the long primary season.

Bernie’s next target? Nevada’s tough housing market and Wall Street’s role in the mortgage foreclosure crisis… https://t.co/DmlQ8llvkB — Megan Murphy (@meganmurp) February 10, 2016

It remains to be seen how much the momentum and fundraising will mean for Bernie Sanders, as polling from Nevada and South Carolina is still light. But if newer polls show him closing the gap in a meaningful way, it could mean trouble for the Clinton camp and the start of a new, wide-open primary.

[Picture by Mark Wilson/Getty Images]