Roman Brown, left and Sam Crawford, right move part of a wall out of their way Sunday, April 14, 2019, as they help a friend look for their medicine in their destroyed home along Seely Drive outside of Hamilton, Miss. after a tornado touched down Saturday night, April, 13, 2019. (AP Photo/Jim Lytle)

April experienced an unofficial total of at least 250 tornado touchdowns, making it the highest level of tornado activity in the U.S. since April 2011. This record number of tornado events in one month contributed to a costly thunderstorm loss bill of several billion dollars.

The first of two major tornado outbreaks occurred April 13–15 in southern and eastern sections of the U.S. At least 70 tornados touched down in Texas, Louisiana, Arkansas, Mississippi, killing at least nine people and causing widespread damage as baseball-sized hail and straight-line winds gusting up to 100 mph tore across the South, Midwest, Southeast, and Mid-Atlantic.

At least 90,000 structures were affected. Total economic losses for this specific tornado event are estimated at up to $925 million, with insurers covering approximately $700 million of the cost according to Aon’s newly released Global Catastrophe Recap, a monthly report that examines natural disaster events worldwide.

Related: 14 electrical safety tips: What to do before, after and during a storm

Other costly April tornado events

The second major tornado outbreak on April 17–19 impacted central and eastern sections of the U.S., killing at least four people. At least 96 tornadoes touched down across a dozen states, nearly half of which were recorded in Mississippi. The outbreak saw widespread reports of damaging straight-line winds and large hail. Aon’s recap says the total economic losses for this event is expected to reach into the hundreds of millions, and a majority of these costs will be insured.

A third series of tornados hit on April 23–25 when 17 tornados touched down across the Plains and Southeast, causing the most damage in Texas and Louisiana from high-winds and flash flooding. At least five were killed. Again, Aon says this storm event will result in hundreds of millions of dollars in losses, a majority of which will be insured.

Related: Lessons that will help home insurers prepare for the 2019 hurricane season

April thunderstorm losses in the U.S.

Aside from April’s high tornado activity, the U.S. experienced several other thunderstorms that resulted in a high price tag.

On April 5–8, thunderstorms in the Southeast created massive damage as high winds and softball-sized hail up to 4.50 inches in diameter impacted Texas primarily, along with Louisiana, Mississippi, and Alabama. This event was estimated to cost $250 million in total economic losses, with insurers covering roughly $190 million of the cost.

Other severe thunderstorms occurred throughout the month, including an April 10 winter storm that affected much of the U.S., but caused the most damage in Colorado, Nebraska, South Dakota, and Minnesota, costing $100 million in losses.

Dozens of tornados and torrential rainfall swept across parts of the Plains, Midwest, and Southeast from April 30 through May 2, killing at least five and costing hundreds of millions in total economic losses, a majority of which (excluding flood losses) will be insured.

Related: Catastrophe planning: Ensuring calm during the storm

Around the world

Other global events resulted in high loss costs, primarily due to flood events.

In Canada, flooding across the St. Lawrence, Ottawa, and St. John River Basins impacted 10,000 structures and cost hundreds of millions. Torrential rainfall in Rio de Janeiro, Brazil killed at least 10 and created widespread structural damage, costing millions. At least 87 people died in South Africa due to widespread flooding and mudslides following heavy rainfall in the provinces of KwaZulu-Natal, Eastern Cape and the Free State.

Related: ‘Unprecedented flooding’ predicted for spring: Here’s how to prepare