Berryessa Lake in Napa County, California attracts numerous tourists each year, as they want to witness the spectacular sight of a hole—often referred to as the “gateway to hell”—that appears in the middle of the lake, swallowing excess water.
In reality, this is not a hellmouth. It is not particularly dangerous, contrary to its appearance. This is a spillway, built by engineers in the 1950s, which has gradually been affectionately dubbed the “Glory Hole.”
This hole serves as an alternative to a traditional side channel design, used to control the outflow of water from a dam or levee.
Berryessa Lake is located in the Monticello Dam.
When the water level in Berryessa Lake rises too high, the excess water begins to swirl into a large hole that is carved deep into the lake’s surface. This structure is known as a bellmouth, which has been used to manage water levels at various dams around the world.
However, the “Glory Hole” in Napa is one of the more famous sites, as it provides a breathtaking spectacle.
To ensure the safety of visitors, the area management prohibits swimming or boating in the vicinity. However, many opinions suggest that the water hole is not as dangerous as it appears.
Some reports indicate that most people, except for children, can easily swim at an average pace and overcome the pull of the whirlpool, even at its peak.
On average, the 22-meter wide and 75-meter long drain can “swallow” approximately 1,360 cubic meters of water every second. After plunging down the hole, the water enters a narrower pipe, which then leads to the nearby Putah Creek after more than half a kilometer of horizontal travel.
The only recorded death at the hole occurred in 1997 when a woman actively swam out and clung to the edge of the hole for 20 minutes. By the time rescue teams arrived, it was too late. Her body was discovered a few hours later.
In the 1950s, when engineers constructed the “Glory Hole,” they believed it would only be used about once every 50 years in extremely special circumstances.
However, since the beginning of this century, the whirlpool has opened a total of three times. This indicates that our planet’s climate is changing at an alarming rate.
