Horrifying 75ft 'portal to Hell' opens up in lake with huge spinning vortex

dailyrecord.co.uk:

A giant water vortex which opened up in a lake has been branded a "portal to Hell". The 75ft-wide chasm appeared in the Lake Berryessa reservoir in eastern Napa Valley, which lies at the top of the Monticello Dam in California, after water levels got too high.Excess water can cause a whirlpool leading to a deep hole.

And while this can look terrifying to unsuspecting onlookers, the vortex in the Lake Berryessa reservoir is the result of careful planning, the Express reports.The phenomenon is known as a 'glory hole' and dates back to the 1950s.

Engineers built the spillway as an alternative to the more common chute, which is used to control the flow of water from dams or levees.The man-made tunnel is around 75ft wide and a whopping 245ft deep and swallows around 48,000 cubic feet of water per second as a failsafe if the level of the lake rises above 15.5ft.The architects chose to construct the chasm rather than the more traditional drainage methods as the narrow gap between the cliffs surrounding the dam would have left a chute with nowhere to dump the water.And in the decades since its creation, the glory hole has enjoyed a burgeoning reputation.

Lake Berryessa can hold around a 52billion gallons of water before the spillway is needed to drain it.In 2018, it reached full capacity for the first time in more than a decade, and in 2019, the "portal" opened again with thousands flocking to Berryessa to watch the awe-inspiring spectacle.The water tunnel poses no threat to safety as the reservoir is cordoned off when it is in use, with swimming and boating prohibited on the lake.