Winter is a killer.

An estimated 80,000 Americans died of flu and its complications last winter — the disease’s highest death toll in at least four decades.

The director of the Centers for Disease Control and Prevention, Dr. Robert Redfield, revealed the total in an interview Tuesday night with the Associated Press.

Flu experts knew it was a very bad season, but at least one found the size of the estimate surprising.

“That’s huge,” said Dr. William Schaffner, a Vanderbilt University vaccine expert. The tally was nearly twice as much as what health officials previously considered a bad year, he said.

In recent years, flu-related deaths have ranged from about 12,000 to 56,000, according to the CDC.

Last fall and winter, the U.S. went through one of the most severe flu seasons in recent memory. It was driven by a kind of flu that tends to put more people in the hospital and cause more deaths, particularly among young children and the elderly.