Crowley Lake Stone Columns Created by Volcanic Activity

Crowley Lake is a reservoir on the upper Owens River in southern Mono County, California. Upon completion of the reservoir in 1941, strange columnar formations, some of which reached heights of as much as 20 feet, were spotted along the reservoir’s eastern shore. Some described them as stone cylinders connected by fortified stone arches that had been completely covered and obscured for millions of years but which had been gradually unmasked by the incessant pummeling of the lake’s powerful waves, whose constant pounding had eroded the more malleable rock at the base of the cliffs encasing these pillars.
The pillars were simply regarded as oddities until 2015, when geologists realized that they were the result of frigid water from melting snow seeping down into volcanic ash, creating tiny holes in the hot ash, which then rose up and out of these same holes. Researchers have now counted nearly 5,000 of these pillars, which appear in groups and vary widely in shape, size and color over an area of 4000 acres, with some of the columns standing as erect as towering pylons.
info: wikipedia