Alaska Democrats will gather in school gymnasiums and community centers around the state Saturday to select delegates to choose the party's presidential nominee.

The Alaska Democratic Party is organizing the caucuses. Alaska will send 20 delegates to Philadelphia in July for the Democratic National Convention, 16 of whom will be elected at the state convention in May based on what happens in the caucuses.

Only registered Democrats, or voters who sign up as Democrats at the caucus site, can participate.

Heading into the weekend's caucuses, former Secretary of State Hillary Clinton had 1,223 pledged delegates and 467 superdelegates; Sen. Bernie Sanders of Vermont had 920 pledged delegates and 26 superdelegates. A candidate needs 2,383 delegates to win the nomination. Superdelegates are usually party or elected officials who are free to support any candidate.

As party officials worked to spread the word about the caucuses, Clinton and Sanders volunteers were running last-minute get-out-the-vote campaigns. The Clinton campaign released a schedule of phone-banking efforts in three Alaska cities and the Sanders campaign advertised campaign organizing meetings in Bethel and Nome and "Rock the Caucus" concert events in Fairbanks and Anchorage.

On Thursday, Sanders' wife, Jane O'Meara Sanders, arrived in Anchorage to campaign for her husband.

How a caucus works

Nearly 8,900 Democrats participated in 2008, the last time the party held a caucus in Alaska. Barack Obama easily defeated Clinton here, winning about 75 percent of the vote.

This year, the Alaska Democratic Party is hosting 42 district caucus locations, mostly at schools and community centers. A list can be found on the party's website. Each caucus site has a different timeline, but officials are generally telling caucus-goers to show up no later than 10 a.m.

In Anchorage, the caucus will be held at West Anchorage High School on Hillcrest Drive. Doors open at 9 a.m. and the caucus "program" is scheduled to start at 10 a.m. Officials say caucus-goers must be present and registered by 10:45 a.m. to vote.

Once the caucus starts, the crowd will divide into state House districts. To receive any delegates, a candidate must have at least 15 percent of voters in a given district.

That amount will be determined at the very start. For example, if 100 people show up to a caucus site, at least 15 voters will have to support a candidate if delegates are to be awarded.

Once the baseline number is set, the voters will "fan out" to show support for a candidate, or none of them. The options will be Clinton, Sanders, California real estate developer Roque "Rocky" de la Fuente or the "uncommitted" camp, Casey Steinau, chair of the Alaska Democratic Party, said in a Thursday phone interview.

How counting happens depends on the district. It might involve caucus-goers going to a corner of the room, by forming lines, or by a show of hands.

If a group's candidate doesn't receive at least 15 percent, a second "fan out" will occur. That's an opportunity for voters in one group to convince voters in another group to come to their side.

"It's really different, as far as caucuses versus just casting a ballot," Steinau said. "It's about being in a place with your neighbors and friends, and actually talking about issues."

After counting, candidates will be awarded state convention delegates proportionally. The Democratic state convention is set for May 13 to 15 in Anchorage.

Caucus day will also include state Democratic Party business, such as electing district officers and taking proposals for changes to the party's platform.

Phone calls and a Sanders rally

Neither Clinton nor Sanders were traveling to Alaska to campaign, but on Thursday, Jane Sanders arrived in Anchorage to help pitch her husband's platform to voters.

Plans for a drop-in dinner with supporters at Moose's Tooth generated so much interest online that the campaign rescheduled it as an evening rally and town hall at Spenard's Lakefront Hotel, formerly the Millennium Hotel. The campaign live-streamed the event online.

In an interview at the hotel Thursday afternoon, Jane Sanders reiterated her husband's position that "too many decisions, both political and economic, are resting in the hands of too few people.

"I think just as many of his supporters are not included in the decision-making. Alaska, because it is remote, is often not included in thinking," Sanders said, interrupted occasionally by a hacking cough that she said she picked up from air travel. "We both wanted to come up here and hear directly."

Sanders said she hopes her presence in the state will make a difference, and she plans to take voters' ideas back to her husband. She said she met with three tribal elders and talked about climate change and called Alaska's practice of contracting with the federal government for Native health services a "success story."

Sanders was scheduled to fly to Dillingham on Friday for events that included a listening session on domestic violence and sexual assault and a meeting with Bristol Bay tribes opposed to the proposed Pebble mine.

"I like to, and Bernie likes to, see things firsthand," Sanders said.

Jane Sanders also plans to participate in a Saturday morning march in Anchorage before the start of the caucuses.

Asked whether Clinton's quite well-known spouse, former President Bill Clinton, would make an appearance in the state, Alana Mounce, statewide director for the Clinton campaign, said, "You would be the first to know."

Mounce said Clinton campaign volunteers had been calling voters in rural areas this week. The campaign also announced "get out the vote" phone banks in Anchorage, Fairbanks and Juneau for Thursday and Friday, and Mounce said calls were also being placed by campaign volunteers in the Mat-Su and the Kenai Peninsula.

Those calls include talking to rural voters about Clinton's stance on issues, such as her opposition to the Pebble mine project, Mounce said. Clinton's campaign also released a list of policy proposals tailored to Alaska, which included promises to address climate change and reform the U.S. Department of Veterans Affairs.

On Tuesday morning, Clinton appeared on an Anchorage pop radio show and took 10 minutes of questions from "Breakfast Club" morning show hosts Malie Delgado and Casey Bieber on a variety of topics. She repeated an oft-used talking point about how she was prepared to work in Washington by a job on a salmon "slime line" in a Valdez cannery in 1969 — a job from which she was fired after a week because, she has said in past interviews, she asked too many questions.

Earlier this week, Clinton's campaign released a long list of political supporters in Alaska, including state Rep. Matt Claman, D-Anchorage, former Democratic state Rep. Katie Hurley, former Gov. Bill Sheffield and Anchorage Assembly Vice-Chair Elvi Gray-Jackson, as well as three former Alaska Democratic Party Chairs — Patti Higgins, Don Gray and Michael Wenstrup.

Susanne Fleek-Green, chief of staff for Anchorage Mayor Ethan Berkowitz, was listed among the supporters. Berkowitz, a former Democratic state representative, wouldn't say Thursday whom he supports.

"Not Donald Trump," Berkowitz said.

Correction: An earlier version of this story indicated that Anchorage's caucus timeline applied to caucuses statewide. Voters should check with individual caucus sites for timelines. The caucuses generally start at 10 a.m.