Breakdown: Weather History - Why February 21, 1971 is a day to remember

MEMPHIS, Tenn. (WMC) - It was a busy day in weather history on February 21 in 1971.

An unusually powerful storm system caused a tornado outbreak and blizzard to occur simultaneously in the U.S.

Known as the Mississippi Delta Tornadoes, they were spawned by a very intense storm system that also produced blizzard conditions in western Oklahoma and central/western Kansas. Snow depths of 2 to 3 feet occurred in northwestern Oklahoma.

Surface Map at 2100z (4 PM CST) as killer tornadoes were on the ground February 21, 1971(NOAA)

On the morning of Sunday, February 21, 1971, a surface low was moving into Oklahoma and a warm front extended east across northern Louisiana, Central Mississippi, into Alabama. South of the boundary, winds were southerly and dewpoints were in the middle 60s at moist air surged northward.

By early afternoon, sunshine had driven surface temperatures to near 80 degrees across the Mississippi Delta. Instabilities were sky high and the diffluent pattern aloft made for an explosive situation.

Just before 3 p.m. CST, an F5 tornado touched down near Delhi, Louisiana. It roared northeast, crossing the Mississippi River into Mississippi. Eleven people died in Louisiana and another thirty-six in Mississippi. The town of Inverness was completely obliterated. Twenty-one people died there.

Around 4 p.m., a family of tornadoes started in Issaquena County, Mississippi. It would produce damage along a 160-mile path all the way to north of Oxford. F4 damage (207-260 mph winds) was caused along much of the path.

The town of Cary was destroyed and 11 people died in the area. 13 people died in an F4 tornado that cut a 70-mile path of destruction through Warren, Yazoo, and Holmes Counties.

Tracks of the Mississippi Delta Tornadoes - February 21, 1971(NOAA)

Overall, 24 twisters were reported. Three tornadoes rated as F4′s accounted for most of the deaths and destruction.

Keep in mind, it is possible that some tornadoes were not reported in 1971 or that one or more were classified as one tornado and was actually several.

This outbreak was unusual, particularly for February, as its is not a typical tornado month (But no month comes with a tornado-free guarantee.)