The National Weather Service estimates that a tornado that hit Bryan County, Georgia had winds of 185 mph (300 kph), making it the strongest twister in the United States so far this year.

The storm killed Belinda Thompson, 66, of Ellabell and injured 12 others, including Thompson’s husband.

A National Weather Service damage survey released Friday upgraded the tornado’s strength to EF-4 on the Enhanced Fujita scale from the original rating of EF-3.

A March 5 tornado that hit Winterset Iowa, with 170 mph (275 kph) winds, killing 6 people, was the strongest-rated tornado until now.

The Georgia storm had a path of nearly 13 miles and was nearly three-quarters of a mile (1.2 kilometers) wide at its widest point.