Mesmerizing, but dangerous. This is an ideal description of the huge “glory hole” on Lake Berryessa.

For the first time in almost a decade, last February, Californians witnessed a rare occurrence- a huge “glory hole” in the reservoir located 75 miles north of San Francisco, draining excess rainwater.

When full of spiraling water, the big drain is truly captivating.

Constructed in the corner as a spillway, the officially called Monticello Dam Morning Glory Spillway, or simply Glory Hole, is a 72-foot diameter, 200-foot deep circular concrete pipe.

Once the reservoir is filled over capacity, which is more than 440 feet above sea level, the spillway allows the excess rainwater to be safely transported to a creek below the Monticello Dam.

It was constructed in 1957 for storm events, and the US Bureau of Reclamation believed it would only be needed every 50 years or so.

Yet, the waters in the reservoir rose to unsafe levels in February of 2017 too, due to the very heavy rain that lasted for several weeks. Previously, it was set into action in 1996 and 2006.

It is illegal to go near the powerful hole, as it can move 48,000 cubic feet of water per second out of the reservoir, even though it has very little suction. The California Bureau of Reclamation also advises visitors to be careful and watch for possible mudslides and debris.

Unfortunately, the glory hole claimed the life of a 41-year-old swimmer named Emily Schwalen in 1997.

Schwalen held on to the side of the spillway for about 20 minutes but was eventually swept inside.

Therefore, even though the hole is hypnotizing and attractive to watch, it should be observed from a safe distance only.

In 2017, YouTube user Evan Kilkus flew a drone over it, so we can all have a closer look!

Sources:
www.theguardian.com
www.lamag.com
www.nytimes.com