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MIssissippi tornado rated a violent EF-4

By: Dr. Jeff Masters, 2:30 PM GMT on April 27, 2010

The devastating tornado that ripped through Mississippi on Saturday April 24, killing ten, was a violent EF-4 twister with 170 mph winds when it hit Yazoo City, according to a preliminary damage survey by the National Weather Service in Jackson, Mississippi. The tornado touched down near Tallulah, Louisiana, crossed the Mississippi River into Mississippi, and traversed nearly the entire state of Mississippi, carving a 149-mile long path of destruction. It is extremely rare for a tornado to stay on the ground this long. The world record longest path by a tornado is the 219-mile long path of the deadliest tornado in U.S. history, the violent F-5 Tri-State Tornado of 1925, which killed 695 people in Missouri, Illinois, and Indiana.


Figure 1. A church in Yazoo City works to restore its toppled steeple after Saturday's tornado. Image credit: J.A.

Saturday's tornado was strong almost from its initial stage of development in northeast Louisiana. EF-2 and EF-3 damage was common all along the tornado's path into central Mississippi with areas of EF-4 damage observed in both Yazoo and Holmes counties. After crossing Interstate 55, the tornado weakened with EF-1 and occasional EF-2 damage being common as the tornado moved across Attala County. The tornado re-intensified as it moved into Choctaw County, with at least high end EF-3 damage occurring northwest of the Weir community. The tornado remained strong before rapidly weakening and then dissipating just after moving into Oktibbeha County. It was the first violent EF-4 tornado of 2010. Over the past decade, the U.S. has averaged five violent EF-4 or EF-5 tornadoes per year. Our severe weather expert, Dr. Rob Carver, has a more detailed analysis of Saturday's tornado.


Figure 2. One mile wide wedge tornado from near Yazoo City, Mississippi on April 24, 2010. Tornadovideos.net intercepted the tornado near Holly Bluff just east of the Mississippi River, and tracked the huge wedge to the damage path in Yazoo City, after which they assisted with the rescue effort until emergency personnel gained control of the situation.

Portlight assesses needs after the Mississippi tornado
Portlight.org volunteer Riki Chomsky (AKA "kitchengypsy") paid a visit to tornado-ravaged Yazoo City, Mississippi on Sunday to assess whether or not Portlight should mount a response effort. Her report:

At this time, Portlight has decided not to deploy an emergency feeding unit to Yazoo City. We base this decision on 3 factors:

1) Scope. Although the scenes of devastation are terrible, by our estimate, more than half the city is relatively unharmed. With several restaurants, gas stations and other services open for business in such close proximity to the command center, we have faith that continuity of operations will soon be established for the whole city.

2) Current efforts: All current relief teams, with special emphasis on the Red Cross and Salvation Army, are doing an excellent job of handling the situation. They have taken pains to ensure food distribution across the affected areas, and we have confidence that they are truly the best organizations for this type of situation.

3) Anticipated Need / Speed of Recovery: although the extent of the damage will most likely require outside work crews, we saw very encouraging signs of progress. Work crews were active at almost every damaged site, which is highly impressive for less than 24 hours after the storm. Even when volunteer crews are brought in, we anticipate their needs being more than adequately met by the existing local churches, who have already started feeding work crews and rescue personnel. In addition to the Red Cross and Salvation Army, Portlight extends our appreciation to all members of this exemplary community response. While the damage is significant, the Salvation Army and local Red Cross seem to be doing a great job meeting the needs there, and Portlight recommends supporting one of these organizations.

Portlight continues aid efforts in Haiti
Portlight continues to focus its energy and funds on the situation in Haiti, where the rainy season is fast approaching the needs for shelter, medical supplies, food and water remain urgent. Their latest effort is a shipment of 10 pallets of Durable Medical Equipment, 30 pallets of water, 7,000 pounds of rice, a number of tents, tarps and various building supplies totaling some 14,000 pounds of goods. The supplies were loaded onto the schooner Halie and Mathew. The schooner was slowed by bad weather on its way to Haiti, and was forced to dock in Jamaica to make repairs. The ship is expected to land in Haiti later this week to deliver its supplies. Please visit the Portlight.org web site or the Portlight blog to learn more and to donate to this worthy cause.


Figure 3. Relief supplies for Haiti earthquake victims being loaded onto the schooner Halie and Mathew.

Jeff Masters

Tornado

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.