Former research scientist at NASA and current physics teacher Dr. Eric Best explains the momentum of the hail stones that fell during the April 12, 2016, hail storm that closed all of Wylie ISD campuses the following day.

“I did a calculation where I found the momentum of the hailstones coming down with about a four inch diameter traveling at a vertical velocity at about 85 miles an hour. We get some really big numbers; the momentum of this thing comes out around 150 foot-pounds per second, which is really large.

If we calculate just the force at the point of impact from the impulse we get something that comes out about 101 pounds, so think about every one of those hailstones about that size coming down hitting your roof with a force of about 101 pounds over a really small area that hits the roof. It’s very easy for that hail to smash its way through the roof, and once it’s done that, it’s not going to have any trouble coming in through the ceilings.

Windshields are also not designed to handle that, and the thin metal and plastic that our cars are made out of today are not designed to handle that. So if you’re thinking “why does my car look like it’s just been attacked from the air?” Just imagine having a 101 pound sledgehammer and going out there and just pounding the car.”

–Dr. Eric Best, physics teacher

Read other stories in this series:

A hail of a tale: Haleigh’s story

A hail of a tale: Kendall’s story

A hail of a tale: Hartman Elementary’s story

A hail of a tale: Syrina’s story

A hail of a tale: part one video