Soaring temperatures, high elevation and a slew of other ingredients collided to create the freak hailstorm that hit Guadalajara, experts said Monday.

Residents of Mexico’s second-largest city woke up in shock Sunday to find that nearly 5 feet of hail had accumulated in some areas, trapping cars and damaging hundreds of homes.

“I’ve never seen such scenes in Guadalajara,” Jalisco Gov. Enrique Alfaro told Agence France-Presse. “These are never-before-seen natural phenomenons. It’s incredible.”

Hail usually occurs during thunderstorms when updrafts carry warm, moist air above the freezing level, condensing it. A hailstone grows as additional water freezes onto it, and eventually becomes too heavy and falls to the ground.

In Guadalajara, which has temperatures nearing 90 in June, more moisture is available, contributing to hailstorms.

The city is situated at 5,000 feet above sea level, and “higher elevation means you are closer to the freezing level, so it’s more common to see hail,” said Accuweather meteorologist James Andrews.

“What’s special about this, is the intensity of the storm and the huge amount of hail that it brought,” he said. “It’s staggering.”

In Sunday’s case, the storm occurred in the early morning, when it was about 60 degrees, and the hail core sat above the same spot for a significant amount of time, Andrews said.

“If you have intense hail falling along with rain and it’s happening in the same place for an extended length of time, you’re going to get tremendous runoff.”

A combination of water and hail moved downslope, because of the local topography, and obstacles, like buildings, likely blocked the flow of hail, allowing more ice to accumulate on top.

“Hail depth from the storm [alone] couldn’t have been that strong,” Andrews said. “That great depth could be accounted for that the hail was running off street like in a flash flood and accumulated in a low spot.”

“It may have just been a freaky coincidence of the local layout,” Andrews said.