April 2011 derecho and tornado outbreak facts for kids

The April 2011 derecho and tornado outbreak was a huge weather event. It brought many tornadoes and derechoes to parts of three states. A derecho is a type of widespread, strong straight-line wind storm. These powerful storms caused a lot of damage and sadly, nine people lost their lives. The event happened over two days, from April 4 to April 5, 2011.

How the Storms Formed

On April 3, 2011, very strong thunderstorms, called supercells, started forming in Illinois. At the same time, a long line of severe thunderstorms, known as a squall line, began in Iowa. These storms brought big hail and strong winds. They might have even caused some tornadoes. Even as heavy rain fell west of these storms, the squall line kept producing severe weather.

By April 4, the supercells in Illinois also turned into a squall line of severe thunderstorms. These storms created tornadoes. Later that day, more supercells formed in Tennessee, also causing tornadoes. As night fell on April 4, the two storm lines crashed into each other and moved towards the east.

By April 5, the severe thunderstorms had reached states like New Jersey, Maryland, Delaware, Virginia, North Carolina, and Florida. They then moved out over the ocean. This storm system produced many tornadoes across these areas. Weather experts issued many warnings for severe thunderstorms and tornadoes to keep people safe.

Where the Storms Hit

Impact in Illinois

Supercells hit Illinois, bringing very large hail and strong winds. Some hail was as big as 4 to 5 inches across! This caused a lot of damage. Tornadoes were also possible in some areas.

Impact in Iowa

A squall line of severe thunderstorms affected Iowa. It also brought large hail and strong winds. Hail here was about 3 to 4 inches wide. While tornadoes were not as likely, they were still a possibility.

Impact in Indiana

Both supercells and squall lines hit Indiana. There were many reports of large hail and strong winds. An EF0 tornado touched down in Indiana. This is the weakest type of tornado. Hail up to 2 to 3 inches wide also fell, along with damaging winds.

Impact in Ohio

An EF1 tornado formed within a supercell and caused some damage in Ohio. This type of tornado is a bit stronger than an EF0. Along with the tornado, strong winds and hail (about 1 to 2 inches wide) were a problem.

Impact in Pennsylvania

An EF2 tornado dropped down in south-central Pennsylvania. This tornado, which is stronger than an EF1, caused significant damage. Hail, about 1/2 to 1 inch wide, also fell during the storm.

Impact in Tennessee

An EF3 tornado caused a lot of destruction in the area where it touched down in Tennessee. This is a very strong tornado. Along with the tornado, there were strong winds and hail that was about 1/4 to 1/2 inch wide.

Impact in New Jersey

Severe thunderstorms affected New Jersey. These storms produced hail that was about 1/10 to 1/4 inch wide. They also brought strong winds. Tornadoes were not very likely but could have happened.

Impact in Maryland

A possible tornado caused some damage in Maryland. Besides the potential tornado, hail and strong winds were also a concern for the state.