For the first time since 1938, children will go trick-or-treating on Halloween in Des Moines, Iowa: NPR

Children in Des Moines, Iowa, can go trick-or-treating on Halloween for the first time in decades and find out why all a person there has to do is look at the sky.

Forecasted storms are forcing a one-day postponement of “Beggars' Night,” the annual tradition attended by children in Iowa's capital city and replacing the Oct. 31 All Saints' Day celebration that is widespread across the rest of the country.

According to the State Historical Society of Iowa, the tradition began in 1938 with the goal of curbing vandalism and violence. This year, Des Moines police responded to more than 500 reports of vandalism on Halloween night, with youths setting fires and throwing bricks. Since then, children have gone trick-or-treating on the night before Halloween, known locally as Beggar's Night, while Halloween is reserved for activities for adults and families, according to the historical society.

In addition to the storms forecast for Wednesday night, there is a risk of tornadoes and hail, according to the National Weather Service.

The tradition involves children telling jokes in return for their sweet treats.

According to the Des Moines Register, Jokes in recent years have included: “How does a cucumber become a cucumber?” It's a harrowing experience?” and “Why don't lobsters divide? Because it’s shellfish.”

Since then, the tradition has spread to other parts of Iowa and Ohio.