CNN WIRE — Bad weather seems to be the worst difficulty so far on election day: VIDEO

By Eric Levenson, Tami Luhby and Jeremy Herb, CNN

(CNN) — American voters headed to the polls Tuesday to choose the country’s next leaders in a mass democratic experiment in which tens of millions of votes will be cast without incident.

Still, scattered issues with voter eligibility; logistical problems such as long lines and bad weather; ballot functionality; and vote-counting will be scrutinized closely this election. That’s especially the case in key swing states amid former President Donald Trump’s false claims of mass election fraud.

As of mid-morning, extreme weather and other “temporary infrastructure disruptions” have been reported in parts of the US, but there haven’t been any “national-level significant incidents impacting the security of our election infrastructure,” said Cait Conley, a senior adviser at the Cybersecurity and Infrastructure Security Agency.

The issues so far are “largely expected, routine and planned-for events,” Conley added.

Bad weather in the Central US could cause some challenges for people attempting to vote. In Missouri, Arkansas and Illinois, a flood watch is in effect until at least 12 p.m. CT for around 4 million people, as persistent and heavy rainfall since Monday has flooded roadways and caused thousands of power outages.

Further, in California, dry air and gusty winds are expected to ramp up for the Bay Area and Sacramento beginning Tuesday morning, which could lead to dangerous fire weather across the region.

There were also some minor reported issues that caused voting delays.

Officials have requested that voting time be extended in Cambria County, Pennsylvania, after a “software malfunction” disrupted voters’ abilities to scan their ballots, the Office of County Commissioners said.

And in Atlanta, two polling locations were closed for about 30 minutes due to non-credible bomb threats, according to Nadine Williams, Fulton County Registration and Elections Director.

“Thankfully these locations are now operational again and all polling sites are secure with an active security presence,” Wiliams said.

Overall, the vast majority of voters express positive views of the voting experience. In a Pew Research Center survey of the 2020 election, 94% of voters said it was very or somewhat easy to vote, while just 6% said voting was very or somewhat difficult. Of the group who said voting was difficult, about half cited logistical issues while voting, such as long wait times at polling places and issues with mail ballots, according to Pew.

In Fulton County, Georgia, on Tuesday morning, Asia Brownlee, a travel nurse, described the process of getting registered to vote as “tedious.” She said she had to place numerous phone calls to become an active voter in Fulton County on the last day of early voting, but work hours forced her to put it off until early Election Day.

“I’m able to make a difference. It’s very important. This is a crucial election,” she said.

More than 161 million votes cast in 2020

Election officials across the US have pledged to uphold the integrity of the vote and urged voters not to be misled by conspiracy theories.

“Here in Georgia, it is easy to vote and hard to cheat,” Georgia Secretary of State Brad Raffensperger said Monday. “Our systems are secure and our people are ready.”

The 2024 election has already featured allegations from Trump and other Republicans that the vote is “rigged.” Trump has made repeated false claims that Democrats are cheating in the election, and he’s twisted isolated problems with voting in an effort to prime his supporters to believe the election is not legitimate if he loses.

He has alleged that voting by noncitizens is a widespread problem, that there’s no verification for overseas or military ballots, that election officials are using early voting to commit fraud and that massive swaths of mail-in ballots are illegitimate. The claims are incorrect and baseless.

Broadly, US elections are an extraordinary undertaking: In 2020, more than 161 million voters cast ballots that were counted across 50 states, the District of Columbia and five US territories, at a total of 132,556 polling places and with the aid of 775,101 poll workers, according to the US Election Assistance Commission.

Federal elections are also largely decentralized, as local jurisdictions have the primary responsibility of tabulating, reporting and certifying results.

The majority of voters are at least somewhat confident that this election will be well run, regardless of which candidate they support, according to a recent Pew Research Center survey.

However, supporters of Vice President Kamala Harris are far more confident, with 90% saying the election will be run smoothly, compared to 57% of Trump supporters. The latter are particularly dubious about whether absentee and mail-in ballots will be properly counted.

Harris supporters are also more confident than Trump supporters that it will be clear who won the election after all the votes are counted, by an 85% to 58% split.

CNN’s Isabel Rosales, Denise Royal, Sean Lyngaas, Sara Murray and meteorologist Elisa Raffa contributed to this report.