People on a tourist boat in the Florida Everglades.

The federal government partially shut down at midnight after Congress and President Donald Trump were unable to come together on a stopgap spending measure. It is the third closure in less than a year.

The shutdown isn’t expected to have any immediate, serious impact on most Americans, as long as it lasts only a few days. The Army will not lay down its weapons. Medicare payments will still be sent out. The Social Security Administration will continue to pay benefits and process new benefit applications.

Although essential government functions will continue, some 380,000 federal employees are likely to be placed on furlough; that means they won't work during the shutdown, and won't get paid for that time away unless Congress passes legislation to retroactively pay them.

Another 420,000 workers considered essential (technically called "excepted" or "exempt") must work through the shutdown, but will likely not get paid until it ends.

In addition, some private contractors to the federal government may continue to provide services through the shutdown while others will not.

The shutdown is considered partial because it affects only federal agencies that haven't yet had their appropriations funded by Congress. Those agencies include the Department of Agriculture, the Department of Homeland Security, the Department of the Interior, and the Department of Transportation.

Other agencies, including the Department of Health and Human Services, already have had their funding approved by Congress.

But the longer the government remains closed, the more problematic the situation could become.

Here’s how the shutdown could affect you.

Travel

Homeland Security's contingency plan (PDF) has deemed that 92 percent of its 60,000-plus employees are essential workers. The Transportation Department will likely keep on about two-thirds of its workforce of about 50,000. So Transportation Security Administration personnel and air-traffic controllers will be on the job—without receiving a paycheck—during the busy holiday travel season.

As workers are furloughed, though, some national parks and monuments may close. That means that if you plan to visit, say, the Everglades National Park in Florida or the Lincoln Memorial in Washington, D.C, you may have to delay your trip.

Mindful of the poor public image of national monuments shuttered, however, the Feds may opt to keep some very visible symbols open to the public, says Paul Light, professor of public service at New York University's Wagner School of Public Service in New York City. 

If the shutdown lasts for more than a few days and you need to renew or apply for a passport, you could run into problems. Without workers, the State Department would have to stop processing applications.

Foreign nationals should also expect delays when it comes to processing work and travel documents. Although the State Department will continue to process visas during a shutdown, that function is partially funded through appropriations, so it could suffer disruptions.

Healthcare

Medicare, which provides health insurance for people 65 and older, and Medicaid, which provides coverage for low-income people, will continue to operate uninterrupted. These programs are part of the Centers for Medicare & Medicaid Services, which is part of the Department of Health and Human Services. The Centers for Medicare & Medicaid Services is already funded through September 30, 2019. The Affordable Care Act, which oversees administration of the health insurance exchanges for individual insurance, would also be unaffected.

Unlike the budget showdown in January, funding for the Children’s Health Insurance Program is not in jeopardy. This program provides low-cost health coverage to children in families that earn too much money to qualify for Medicaid, and funding for the program ran out last fall. As part of the budget deal struck in January, the Children’s Health Insurance Program received funding for 10 years.

Disaster Help

Federal Emergency Management Administration employees who respond to disasters will continue to work. However, back-office operations will likely cease or slow. FEMA would furlough about 4,400 employees—about a fifth of its staff—according to the Department of Homeland Security, which runs the department. 

"When you have someone face-to-face with the public responding to a national disaster, those are likely to be deemed essential," Light says. "It’s the back office people, processing the paperwork for disaster relief, loans, grants who will get pulled."

As a result, those who have applied for FEMA housing assistance may have wait, Light says. 

The FEMA-administered National Flood Insurance Program will continue to process and pay claims for its 5 million policyholders, says Cynthia DiVincenti, vice president of government programs for National Flood Services, a private contractor that administers the program's policies.

"However, during a shutdown, the National Flood Insurance Program will not be able to issue new policies, issue increased coverage on existing policies, or issue renewal policies," DiVincenti says.

General Government Assistance

Depending on how long the shutdown lasts, Americans could run into other problems as well, such as getting up-to-date information from government websites. Applications for grants, for example, would also halt as federal agencies stop processing applications.

You'll still get your Social Security benefits and be able to depend on Medicare to cover the medical bills it covers now. According to the Social Security's contingency plan, [PDF] the agency also will continue to process new benefit applications. But if you seek verification of your benefits, want your earnings record updated or corrected, or need to replace your Medicare card, you will have to wait until after the shutdown.

The same goes if you are applying for a mortgage. “By law, any mortgage loan approval is subject to review by the mortgage lender of the borrower’s federal tax returns,” says Tim Ross, CEO of Ross Mortgage, based in Troy, Mich. Because the lender depends on IRS employees to provide and confirm those tax returns, it will have to wait until they are back at work.

Taxes

Tax deadlines remain in place. If the shutdown were to continue into mid-January, seniors and self-employed people would still have to submit their estimated quarterly tax payments by the normal, January 15, 2019 deadline, says IRS spokesperson Eric Smith.

With the exception of victims of federally declared disaster areas, who were granted extensions, "the tax deadlines are unchanged," he says.

The majority of workers at the Internal Revenue Service will likely be sent home, according to the agency's contingency plan [PDF] However, computer experts and other essential personnel are likely to work through a shutdown to ensure the agency's website continues to operate, and that the 2019 tax season begins, as planned, in late January.

If the shutdown were to last into the new tax season, the IRS would postpone paying refunds. But private tax-prep companies could step in the breach with refund advances—in past tax seasons, a popular product for early filers. 

"H&R Block will continue to assist the millions of taxpayers who need to submit their 2018 tax returns and who want their tax refund as soon as possible," a company spokesperson told us.