When Jotaka Eaddy, the founder of Black women's leadership network Win With Black Women, heard Sunday that President Joe Biden had decided he wouldn't run for reelection, clearing the way for Vice President Kamala Harris to become the Democratic Party's first Black woman presidential nominee, her first thought was "Oh my God, what a time to be alive."

Her second? "Oh, our Zoom call tonight -- I'm gonna have to shift the agenda."

Formed in 2020, Win With Black Women has met by Zoom most Sundays for almost four years, drawing hundreds of attendees and support from names like Oprah Winfrey and Dionne Warwick. But Eaddy said they had never had a call anything like this past Sunday's, which drew tens of thousands of viewers, raised more than $2 million for the just-launched Harris campaign, and inspired a similar call led by Black men the next night that raised $1.3 million more for Harris' campaign.

"We thought, 'Well, we probably gonna hit 1,000 [people]. And so we were prepared for 1,000," Eaddy said. "I knew something was different when at about 8 o'clock ... I couldn't get in my own Zoom because it was at capacity."

Win With Black Women's Zoom call this past Sunday -- joined throughout the night by prominent Black woman politicians such as Ohio Rep. Joyce Beatty, California Rep. Maxine Waters and Former Democratic National Committee Chair Donna Brazile -- could herald a surge of support from Black voters and organizers, women, in particular, who could make up lost ground for Democrats in critical battleground states and down-ballot races nationwide.

Black voters helping to swing red states blue

Many Georgia Democrats are looking to the change at the top of the Democratic ticket to help keep Georgia blue.

"For all of our clients, we will need to revise our projections for turnout upward," Georgia Democratic strategist Amy Morton told her team Tuesday after a flood of Harris endorsements early in the week. "That's the impact Harris will have on the ticket."

Since Biden announced on Sunday that he was leaving the 2024 race, Harris has secured commitments from enough delegates to become the presumptive nominee if they all honor their commitment when voting, according to ABC News reporting. And Morton said having Harris as the nominee "is energizing" to the party and could lead to high turnout rates with voters.

"Black women have been critical to Democratic victories in Georgia for as long as I've been working in local space," Morton continued. "And I think that having Harris at the top of the ticket is energizing for all Democrats."

"I expect to see turnout in November that approaches 2020 levels," she added. In 2020, the voter turnout rate was the highest for any national election since 1900.

Georgia played a crucial role in Biden's 2020 victory, going blue for the first time since 1992 due in significant part to organizing efforts from former Georgia Rep. Stacey Abrams, who spent years spearheading get-out-the-vote efforts in Black communities.

In North Carolina, another Southern battleground state with a large Black population, many Democrats said they hope that Harris could reproduce the energy that powered former President Barack Obama to the party's last presidential-election victory in the state in 2008.

"President Obama was the last one who was able to mobilize Black people the way that he did back when he ran for office in '08 and '12," said Aimy Steele, who leads a North Carolina voter engagement organization focusing on Black and Hispanic voters.

Black voter turnout peaked in North Carolina in 2008 with a record 73% of Black registered voters turning out to vote, according to North Carolina's Board of Elections. For comparison, 2016 saw 64% and 2020 saw 68% in the state,

But with Harris at the top of the ticket, Steele said, "I expect the same thing to happen again, if not exceed what he was able to do."

Hoping to ensure that happens, several Black groups have responded to grassroots enthusiasm for Harris with new efforts to mobilize voters to the polls.

Quentin James founded Collective PAC, an organization that supports Black candidates at all levels of government around the country. James helped organize the Monday night Win with Black Men Zoom call -- telling ABC News that the call was just the beginning.

"As someone who's done a lot of fundraising, I've never raised $1.3 million over three or four hours from grassroots donors, I've never seen that kind of momentum," James said. "The energy is inspiring. Each one of those people on the call can organize 10 people or 100 people, and we hope to mobilize all of them."

On Monday, the presidents of the group of nine historically Black sororities and fraternities known as the "Divine Nine" wrote in a press release that they had agreed to collaborate on "an unprecedented voter registration, education, and mobilization coordinated campaign."

Harris joined Divine Nine sorority Alpha Kappa Alpha when she attended Howard University, a historically Black university.

Alpha Kappa Alpha International President Danette Anthony Reed said there is enthusiasm among the sorority's ranks for Harris as a candidate.

"We are just ecstatic and excited that a member of our organization, as well as the first woman of color, has the opportunity to become a candidate for president," Reed said.

'We know when we organize, mountains move'

Already the campaign is seeing the return on Harris' momentum. The campaign has reported a record-breaking $126 million in donations in the 48-hours after Biden's endorsement. The campaign said 74,000 of those who donated were from new recurring donors, with two-thirds of these recurring donors signing up for weekly donations. There has also been a surge of 100,000 volunteers, according to the campaign.

Although there are few polls out that have data to fully capture this moment, Harris is already seeing significantly higher numbers in favorability with Black voters. Black voters in April or June who split 70% for Biden to 23% for Trump in previous polling, now break 78% for Harris to 15% for Trump, according to a CNN/SSRS released on Wednesday.

In a memo outlining the campaign's path forward Wednesday, Campaign Chair Jennifer O'Malley Dillon wrote that the vice president has "multiple pathways to 270" thanks to her support among different groups of voters, including Black, Latino and women voters.

Recently, Harris delivered remarks to another Divine Nine sorority, Zeta Phi Beta, which, like AKA, was also founded at the vice president's alma mater, telling the women that "we know when we organize, mountains move."

Lois Lofton-Donivei, a teacher from Houston, Texas, heard Harris' call and was ready to answer it.

"I'm ready to hit the pavement and to do whatever I can to get her elected as the first female president," said Lofton-Donivei. "We're finally acknowledging that women have the ability to lead."