[3][nb 1] A large low pressure system raced across the Northern Pacific before reaching the coast of the Southern Alaska Panhandle on March 17.
A new low formed from the original one and moved quickly southeastward through Canada and the Great Plains before turning eastward over Northern Oklahoma during the afternoon of March 19.
Favorable conditions in the atmosphere led to a massive area of strong and severe thunderstorms that produced damaging winds, large hail, heavy rain, flooding, lightning, and tornadoes.
A sharp increase in the annual average E/F0–1 count by approximately 200 tornadoes was noted upon the implementation of NEXRAD Doppler weather radar in 1990–1991.
[14][nb 5] 1974 marked the first year where significant tornado (E/F2+) counts became homogenous with contemporary values, attributed to the consistent implementation of Fujita scale assessments.