Residents of Kansas and Missouri were urged to stay indoors after massive pieces of “gorilla hail” pelted on the bordering states causing severe traffic along Interstate 70, Kansas City Star reported.

According to American media, at least one unconfirmed tornado was reported in Kansas while the National Weather Service (NWS) said quarter-size hail was expected across northern Kansas overnight until 6am on Thursday.

Descriptions of the hail ranged from the size of golf balls and apples, to softballs and baseballs, which Alex Sosnowski, senior meteorologist at AccuWeather, deemed to be “gorilla hail”.

The term was coined by Reed Timmer, a storm chaser who calls himself an extreme meteorologist.

“When you get up to tennis ball, baseball-sized or God forbid softball-sized, that can do a tremendous amount of damage, and if you get hit in the head, that could be fatal,” Sosnowski said.

Images of large hail chunks and at least one cracked windshield were shown on KSHB-TV.

The weather service issued a severe thunderstorm watch for parts of Illinois, Iowa, Missouri and Kansas until Thursday morning, then forecasters predict the storm will move east.

However, heavy rain and high winds are still possible from northeastern Texas to central Missouri.

Additionally, Sosnowski said that torrential rain from central Louisiana up through central Arkansas is expected on Friday.