The rotating cloud tower did trigger a tornado warning, with funnel clouds spotted at 8:35 p.m. last Friday. The warning also predicted “two inch hail.” The National Weather Service received “multiple reports of golf-ball to tennis-ball size hail … on the east side of Redding from 8:05 p.m. to 8:20 p.m.” No tornado touched down.

A storm this powerful would be impressive even by Oklahoma standards, but to see something like this in California is incredible. Since bookkeeping began in 1950, California has seen only three instances of hail topping 2.5 inches in diameter — placing the Redding cell among the elite.

Walfoort was in Cottonwood when she snapped the picture. Her photo shows the rotating updraft of the storm, where warm air spirals inward and upward, in the foreground. Behind this corkscrew updraft tower is probably a narrow shaft of heavy rain and hail. In the distance, the storm’s pink and violet anvil can be seen spreading outward downwind. From time to time, sheet-light crackles of lightning can crawl along this 10-mile-high anvil.

LP supercells tend to be the most visually stimulating storms since they have little rain obscuring their structure — that’s where the “low precipitation” part comes from. While they can produce all modes of severe weather, LP supercells are often smaller and may mark a phase at the end of a supercell’s life cycle. But don’t be fooled — LP supercells are dangerous; they can, and occasionally do, produce tornadoes.

Fortunately, Walfoort was safely west of the circulation. And as the layered stack of clouds drifted east like an airborne birthday cake, she witnessed a meteorological marvel.