The tornado death toll for 2011 stands at 537 as of June 17, making it the deadliest year for tornadoes since 1936, according to preliminary data from the Storm Prediction Center.
The staggering death toll puts the 2011 tornado season in infamous company. Since 1875, only six other years have seen more than 500 tornado-related deaths, according to data from the National Severe Storms Laboratory in Norman, Okla. See where 2011 ranks in the top 5 killer tornado years in U.S. history.
Tie 1896 & 2011: 537 deaths
This year's season has seen historic killer tornadoes, including an EF-5 storm on the tornado damage scale that killed 151 people in Joplin, Mo., in May. That storm was a month after the other major killer storms of the season swept across the South on April 27, killing more than 300 people.
Part of the reason this tornado season was so deadly was the number of EF-5 and EF-4 tornadoes, the highest ratings on the damage scale. The fact that several tornadoes hit populous cities straight-on also contributed to the high death toll.
In 1896, one particularly deadly storm, dubbed 'The Great Cyclone,' struck on May 27 as a part of a major tornado outbreak. The storm was rated as an F4 and killed roughly 250 people.
1927: 540 deaths
Records before 1950 are sketchy at best, but on April 12, a tornado reportedly killed nearly 72 people in Rocksprings, Texas. On Sept. 29, another powerful tornado killed 79 people in St. Louis, Mo.
The Rocksprings tornado was an F-5 on the original Fujita intensity scale that occurred well south of the normal bounds of Tornado Alley , according to the NWS office in Amarillo, Texas. The tornado was reportedly a mile wide when it hit the town, destroying 235 of the town's 247 buildings. It injured one third of the town's population, according to the NWS.
1917: 551 deaths
An eight-day tornado outbreak from May to June claimed at least 382 lives across the Midwest and the Southeast. The cities of Mattoon and Charleston in Illinois were the hardest hit, with 101 deaths. The tornado that struck them was later determined to be an F-4, according to the National Weather Service office in Lincoln, Illi.
In Mattoon, nearly 500 houses were demolished, according the NWS. Newspapers at the time reported straw driven half an inch into a tree, photographs and books found 50 to 70 miles away, and a pump and 14 feet of water sucked out of a well.
1936: 552 deaths
A tornado now estimated to have been an F-5 on the old Fujita scale hit Tupelo, Miss., on Apr. 5, killing 216. One day later, a tornado wrecked Gainesville, Ga., killing 203 people. The total outbreak spawned 17 tornadoes that touched down in Arkansas, Mississippi, Alabama, Tennessee, Georgia, and South Carolina, according to the Digital Library of Georgia.
President Franklin D. Roosevelt was vacationing in Florida at the time of the disaster. He cut his vacation short and traveled to Gainesville on April 9, meeting American Red Cross, Civilian Conservation Corps, Works Progress Administration and local officials, according to the Digital Library.
1925: 794 deaths
1925 is the tornado season that stands head-and-shoulders above the rest. An astonishing 794 people died from tornadoes that year, the majority of them from a single, astoundingly deadly twister.
On March 18, the so-called Tri-State Tornado swept through southeast Missouri, southern Illinois and southwestern Indiana, killing nearly 700 people. Several towns were virtually wiped off the map. [Related: What Day Had the Most Tornado Strikes?]