BIRMINGHAM, Ala. – A dangerous tornado outbreak which started on Friday evening continued into the first half of the weekend with at least 18 deaths across the nation’s heartland and South.Saturday’s round of tornadic storms caused damage in parts of Mississippi and Louisiana and triggered the issuance of a rare Tornado Emergency around the town of Taylorsville.Farther south, emergency crews reported a tornado strike in Kentwood, Louisiana, causing damage to several homes and downed power lines, according to the Tangipahoa Parish Sheriff’s Office. One person needed rescue, but there were no known significant injuries, deputies said.WHAT IS A ‘TORNADO EMERGENCY’?Days ahead of the event, the Storm Prediction Center issued a threat level of a 5 out of 5 on its severe storm risk scale and warned of the potential of EF4 or greater tornadoes.The first tornadoes of the event were reported in Arkansas and Missouri on Friday before the threat moved over the South on Saturday.The SPC received at least a dozen reports of twisters on Saturday, with most occurring in Mississippi and Alabama.EARTHQUAKE STRIKES MISSISSIPPI AS TORNADOES TEAR THROUGH STATERadar imagery covering Walthall County in Mississippi showed at least two significant tornadoes just about 45 minutes apart on Saturday afternoon.Widespread damage was reported around Tylertown, Mississippi, and at least 3 deaths are being blamed on the severe weather.First responders said they were still performing damage surveys in the region and the number of victims could change as they comb through debris in the hardest hit areas.Data from Findenergy.com showed more than 50,000 customers from the three states of Louisiana, Mississippi and Alabama were without power as of Saturday afternoon.Initial surveys conducted by National Weather Service meteorologists of the strongest tornadoes indicate that winds were at least EF3 in strength, with winds upwards of 165 mph.Damage surveys were expected to continue for several more days, and the FOX Forecast Center said it was possible that survey crews could find evidence of even stronger twisters on the Enhanced Fujita Scale.The rating scale runs from EF0 to EF5, with EF0 representing weak tornadoes and EF5 being the most extreme with winds over 200 mph.MULTIPLE DEATHS IN MISSOURI, ARKANSAS AFTER MONSTER TORNADOES CAUGHT ON VIDEO AMID SEVERE WEATHER OUTBREAKThe Storm Prediction Center issued several Tornado Watches from Louisiana into Tennessee and Georgia, but most watch boxes are expected to expire before midnight.The SPC says there is a greater than 95% chance of at least two tornadoes in the watch area and a similar greater than 95% chance of 1 or more tornadoes of at least EF-2 strength. But beyond that, the SPC warns conditions are ripe for tornadoes to reach “violent” strengths, rating EF-4 or higher on the Enhanced Fujita Scale.”Multiple, destructive EF3-EF4+ tornadoes are likely,” SPC said.The region had already been placed in a dire and rare Level 5 risk on its five-point severe weather risk scale for portions of Alabama and Mississippi, including Birmingham, Tuscaloosa, Jackson and Hattiesburg. It means a high likelihood of supercell thunderstorms capable of producing tornadoes and damaging winds.THE SPC 5-POINT SEVERE THUNDERSTORM RISK CATEGORY SCALE EXPLAINEDThe end of the multiday severe weather outbreak will happen Sunday when nearly 70 million people from the Northeast to Florida face a risk of severe weather. The worst of the storms are expected from Virginia to Florida, where a Level 2 out of 5 risk exists. Hail and damaging winds are the primary concerns, but an isolated tornado cannot be ruled out especially over the Carolinas. The threat of thunderstorms has already altered some early St. Patrick’s Day Celebrations and tee times at The Players Championship in Ponte Vedra Beach, Florida.HOW TO WATCH FOX WEATHER