(CNN) Since the Centers for Disease Control and Prevention on Tuesday warned that it's not a question of if, but when the novel coronavirus will spread in the United States, some places have already issued emergency declarations, and more could be coming from cities, counties and states.

So far, there are 60 confirmed cases of the virus in the country, and the CDC says that Americans should be prepared in case it spreads.

Here's why local governments are issuing emergency declarations, and what that means for you.

Why emergency declarations now?

Tuesday, Dr. Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Disease, said she's expecting the coronavirus to spread

"It's not so much a question of if this will happen anymore, but rather more a question of exactly when this will happen and how many people in this country will have severe illness," Messonnier said.

"We are asking the American public to work with us to prepare in the expectation that this could be bad," she said.

She said CDC officials have been saying for weeks that while they hope the spread won't be severe in the United States, they are planning as if it could be.

The CDC still doesn't know what that will look like, she added. Community spread could be reasonably mild or very severe.

Since then, local governments have been issuing their own emergency declarations so they can step up preparations.

Why issue an emergency declaration?

Doing so helps free up resources to prepare to fight the disease, should it spread in the United States.

Take San Francisco, for example. Tuesday, the city declared a local emergency , even though it has no cases of the virus, but because it's a major travel hub, especially to and from Asia.

That move will help the city be ready to confront and contain the virus, officials said, for example by freeing up staff so they can focus on preparedness and prevention.

The CDC and other health officials stress there's no reason to be overly concerned yet. The virus "is not recognized to be spreading in US communities," the CDC said Tuesday. But preparation is key.

"Things are stable here," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said Wednesday on CNN's "New Day." "But we need to be ready."

For now, the emergency declarations and preparations by authorities are out of an abundance of caution.

Should I be worried?

The short answer is no, not yet. But you should be prepared.

For most of us, preparation means getting ready for disruptions the emergency measures may eventually bring to our everyday lives -- for example, figuring out in advance what to do if schools and day care centers are closed as a precautionary measure.

But not every community will take those steps. For example, New York City Department of Health officials said that would only happen there in "extreme" situations.

What should I do?

Aside from taking the precautions urged by every health professional -- wash your hands frequently, see a doctor and don't go to work if you feel sick -- being informed is, as always, a first line of defense.