The Enhanced Fujita Scale is used to assign tornadoes a rating based on estimated wind speeds and damage.
The EF Scale became operational on Feb. 1, 2007. It was revised from the original Fujita Scale, developed in 1971 by Tetsuya Fujita, to better reflect wind speed with damage observed in tornado surveys.
Deadly Severe Weather Facts & Safety Tips:
A wet start to the weekend across Spain with flooding rain threatening northwestern areas will turn into a chilly Valentine's Day.
A storm will bring snow and ice that will lead to slippery travel along a 1,500-mile swath from northern Arkansas and Georgia to Maine early next week.
The coldest air of the winter will plunge southward across much of the eastern United States and will feature single-digit and sub-zero temperatures in the Northeast during Valentine's Day weekend.
A blast of arctic air will be accompanied by flurries and even a localized wall of snow in some communities in the Northeast and parts of the Midwest at the start of the Valentine's Day weekend.
Heavy rain will raise the risk of flooding across more than a dozen states in the Southeast on Presidents Day to the East Coast on Tuesday.
The dry, summerlike heat sweeping Southern California will continue through the weekend into early next week.
Southern Calif. (1992)
A 2 day rainstorm brought flooding and mudslides to the area. 12.53" of rain fall at Woodland Hills.
Cherry Hill, NJ (1999)
An F1 tornado causes significant damage to 10-15 homes.
San Francisco, CA (2001)
High only 44 degrees, record low maximum for date.