In Case You Were Wondering

Did you wonder about the 1 – 2 m of hail in Mexico?

Did you ponder the physics of hail piling cars at funny angles?

Did you blame the Guadalajara Council for not declaring a climate emergency?

In this photo released by Jalisco State Civil Defense Agency, cars are piled up after a hail storm in Guadalajara, Mexico, Sunday, June 30, 2019. Officials in Mexico’s second largest city say a storm that dumped more than a meter of hail on parts of the metropolitan area damaged hundreds of homes. (Jalisco State Civil Defense Agency via AP)

Wonder no more:

It was clearly a dramatic and extremely impressive event with major local impacts–but I think the physical characteristics have been fundamentally mischaracterized. I have no doubt there were 1-2 meter hail drifts in some spots (photos attest to that)–but those drifts were clearly created by flash flooding down streets and culverts in a highly urbanized area. (A strong clue are the cars stacked on top of each other–water did that, not hail!). Come to think of it, the physical constraints of a single storm dropping 6+ feet of actual solid ice would probably be prohibitive anywhere on Earth, I would think. I don’t know the exact numbers, but even just considering the amount of column water or the vertical forces required to loft that much solid water…well, suffice it to say it would stretch credulity.

Daniel Swain, a climate scientist at the University of California-Los Angeles.