Doors are closed in the Iowa caucuses. Here are the early leaders. [View all]

[brooklynite]

CNN

It's 7 p.m. local time in Iowa, which means all 1,678 precinct locations have shut their doors to start caucusing. Early entrance polls show Joe Biden, Pete Buttigieg, Bernie Sanders and Elizabeth Warren leading.

Here's what happens now: Neighbors will hear messages from the state party chair, local officials and possibly campaign representatives. They will then show their first preference for president.

Voters will split up into different sections of the room dedicated to their presidential candidate of choice. Typically, a candidate needs 15% of the vote to remain viable, as determined by the amount of people participating in the precinct location. Smaller locations may have different viability thresholds.

After that: If a candidate is not viable, their voters can realign to another viable candidate or join together to create a group in support of another candidate that meets the threshold.