These are the 20 days in the past 100 years when America saw the most deaths from a single catastrophe. Over half are in the past 2 weeks.

• December 16 was the deadliest day of the US's COVID-19 epidemic so far, with 3,448 deaths reported.
• That also makes it the day with the most American deaths from a single catastrophe since at least 1920.
• Of the 20 days with the most fatalities from a catastrophe in the past century, 17 were this year.
• Twelve happened this December.

On December 16, the US reported 3,448 COVID-19 deaths - the most of any day of the pandemic so far.

That was more than the 2,977 people killed on 9/11. It's more than the 2,390 Americans killed in the attack on Pearl Harbor and more than the 2,500 US troops killed on D-Day. It's even a higher death toll than that of the 1928 Okeechobee hurricane, one of the deadliest natural disasters in US history.

In fact, more American deaths from a single catastrophe were reported on December 16 than on any other day in the past 100 years.

Of the 20 days with the most death from a catastrophic event in the past century, 17 have occurred this year. Twelve of those days have happened in December.

The chart below summarizes the 20 days in the past 100 years with the most American deaths from a natural disaster, war, or pandemic. The Pearl Harbor attacks had made the top 20 until Wednesday, which formally bumped it off the list.

More than 200,000 people are getting COVID-19 every day

The US's latest surge in coronavirus deaths and cases began in October, and it's by far the worst. According to The COVID Tracking Project, at least 112,816 Americans were hospitalized with COVID-19 as of Wednesday. That's almost twice as many as were hospitalized during the first surge of infections in April, which peaked with fewer than 60,000 hospitalized people.

During that first surge, the US's deadliest day was May 7, when 2,752 deaths from the virus were reported. Six days in December have already eclipsed that high. In the past week, an average of 211,221 Americans per day have received COVID-19 diagnoses, and the country is averaging 2,507 deaths per day. Since October 1, more than 9.59 million Americans have gotten sick and more than 99,000 have been killed.

"In January, we will pass 400,000 deaths," Ashish Jha, the dean of public health at Brown University, said in a tweet on Sunday. More than 305,000 people in the US have died of COVID-19 thus far. "Those deaths will come from infections that have already happened or will this week," Jha added.

"Vaccines will help," he said. "But we can, must do more."

The 1918 flu pandemic caused more deadly days

The chart above looks only at the past century, and it leaves out leading daily causes of death like heart disease that can't be attributed to a single event or disaster.

Before 1920, the US saw many days with significant catastrophe-related death tolls. The Galveston hurricane of 1900 killed an estimated 8,000 people on September 8 alone, according to the National Oceanic and Atmospheric Administration. And about 3,650 troops died during the Battle of Antietam on September 17, 1862.

The San Francisco earthquake of April 18, 1906 killed more than 3,400 people, according to a fatality count by the archivist Gladys Hansen. And the San Ciriaco hurricane on August 8, 1899 killed 3,369 people in Puerto Rico. (It's likely that many of the deaths related to these two disasters occurred over a subsequent period of weeks, though.)

At the height of the influenza pandemic of 1918 - from September 1 to December 31 of that year - an estimated 381,019 people in the US died, according to a PolitiFact analysis. That's an average of 3,123 people a day.

Vaccines will most likely curb spread - but not for several months

On Friday, the FDA authorized Pfizer and BioNTech's coronavirus vaccine - a major step forward in the US's effort to end the pandemic. Moderna's is likely to follow within days.

But both companies still need to make many millions more doses before the vaccines can make a dent in stopping the coronavirus. Until then, the US's only way to curb rising cases is through the public-health measures we already know: mask wearing, social distancing, and restrictions on gatherings and business operations when necessary.

At least 35 states have mandated mask-wearing in public places.

Gov. Gavin Newsom of California was the first to announce a new statewide stay-at-home order, which took effect in four of the state's five regions over the past two weeks. The only other states with statewide stay-at-home rules are Ohio and North Carolina, which have evening curfews. Other states, including Delaware and Pennsylvania, have announced stay-at-home advisories.

Gov. Andrew Cuomo of New York ordered indoor restaurants to close in New York City on Monday; other states like Michigan and Oregon also have partial or complete bans on indoor dining.

"December and January and February are going to be rough times," Centers for Disease Control and Prevention Director Robert Redfield said on December 2. "I actually believe they're going to be the most difficult time in the public-health history of this nation, largely because of the stress that it's going to put on our healthcare system."

In other words, the coming days could replace some, or most, of the dates in the list above.