Earth Changes
It happened around 5:00 pm Thursday in a parking lot adjacent to the stilling basin, also known as the tubes.
The U.S. Army Corps of Engineers says the sinkhole developed as a result of sustained high releases from the lake.
They say there is no threat to the safety of the dam.
Releases from the stilling basin continue on the opposite side until the sinkhole can be further investigated.
The area around the stilling basin has been closed to the public until further notice.

Lava flows down the banks of the Colima Volcano, also known as the Volcano of Fire, near the town of Comala, Mexico, Friday, July 10, 2015.
The activity at the Colima Volcano began Thursday and continued Friday morning. The volcano is also known as the Volcano of Fire.
Luis Felipe Puente is director of Mexico's civil protection agency. He tweeted Friday that preventive protocols were activated.
A statement from Colima state's civil protection agency on Thursday said the initial eruption occurred just after 11 a.m. Ash was falling to the southwest of the crater. People were advised to recognize a 3-mile (5-kilometer) perimeter around the peak.
A state helicopter was making a reconnaissance flight Friday morning.
The ash spewing from the volcano on Indonesia's main island of Java sparked chaos for vacationers as airports closed and international airlines canceled flights to tourist hotspot Bali, stranding thousands.
Mount Raung in East Java province, about 150 kilometers (95 miles) from Bali's international airport, has been rumbling for several weeks. The level of activity increased in the past week and on Friday it blasted ash and debris 3,800 meters (12,460 feet) into the air.
Government volcanologist Gede Suantika said the eruption forced authorities to close five airports due to the risks posed by volcanic ash, though two airports on Lombok island reopened Friday afternoon. The Transport Ministry told airlines to avoid routes near the mountain. It said a decision about reopening other airports would be made later Friday.
Suantika said lava and ash fall from the 3,332-meter (10,930-feet) -high mountain on Indonesia's most densely populated island also caused the government to urge people to stay away from a three-kilometer (two-mile) -high danger zone around the volcano.
Evacuation of residents living near the volcano is still considered unnecessary, but authorities are urging people to wear masks.

File photo of bison. Anthrax has been confirmed as the cause of death in two Saskatchewan bison, may be cause in seven other deaths.
Anthrax, with is caused by the bacteria Bacillus anthracis, can survive in spore form for decades in soil. Changes in soil moisture, from flooding and drying, can lead to a build-up of the spores on pastures.
Livestock become infected when they eat forage contaminated with spores.
Ruminants such as bison, cattle, sheep and goats, are highly susceptible, and horses can also be infected. While swine, birds and carnivores are more resistant to infection, farm dogs and cats should be kept away from carcasses.
The carcass of any animal suspected of having anthrax should not be moved or disturbed and should be protected from scavengers to ensure the spores from spreading.

The first calf born to the transferred Yellowstone Park bison herd at the Fort Peck Reservation was born April 22, 2012. Eighteen bison from this original herd were found dead on the Fort Belknap Reservation last Sunday.
Repeated requests for comment from Fort Belknap tribal officials went unanswered Wednesday, however, a Facebook posting by the head of tribe's buffalo management program fleshes out the details of what is known.
"There were 17 head of buffalo that were found dead on Saturday mid-morning," states a post from buffalo wrangler Bronc Speak Thunder, "so between Thursday night and Saturday morning something happened that is yet to be determined. Also, one appeared in good shape and no symptoms of being anything wrong died between the time I left Sunday night to early Monday morning, making it 18 total."
The giant sinkhole located not far from Gazprom's Bovanenkovo gas field in Russia's northern Yamal Peninsula has been expanding, scientists said as cited by Yamal region TV. The researchers also discovered additional smaller craters appearing around it, the media said. The whole area is within Russia's key strategic oil and gas region - the Yamalo-Nenets Autonomous Okrug.
The crater, discovered last year, has been gradually filling up with water and turning into a lake. Over the past winter and spring the water level in the crater has risen by 10 meters and it will continue to rise, scientists said, according to the government website of the Yamal-Nenetsky region.
"I am very surprised by the size, it's very big!" Japanese reporter for Asahi Shimbun Terukhiko Nouse, who accompanied the science expedition, told local TV. "And the sound of the glacier melting...this sound amazes me."

This pane of glass at the Minnesota Zoo was shattered Monday but remained in place after a bear slammed a rock against it several times.
The five-layer pane stayed in place "like a windshield," and no creatures on either side of the multiple panes were harmed, said zoo animal collections manager Tony Fisher.
The rambunctious bear and two other grizzlies in the open-air exhibit were called back inside, and the area remains closed to the public until a temporary fix can be made. Later, a permanent pane will be custom-made and installed at a cost of tens of thousands of dollars, Fisher said.
The species had never previously been found in the waters around Singapore or peninsular Malaysia.
Oil industry worker Mr Jailani Salleh told The Straits Times that he spotted the dead mammal under a jetty at around 7.45am and posted a video of it on Facebook.
Mr Marcus Chua, curator of mammals and birds at the Lee Kong Chian Natural History Museum, was informed and told The Straits Times it was an "exciting find". It is to be studied by scientists.
The museum will now work to preserve the specimen, believed to be a young adult. A museum volunteer then informed Mr Chua about the incident at about 9.30am.
The death of two sisters in Chamoli in a leopard attack is the latest incident in the series of man-animal conflicts in the state. Leopards have killed five persons in June.
Experts say the death toll might break the all-time record by the year-end. Rapid changes in the forest eco-system, mainly owing to excessive human intervention and climate change, have been forcing wild animals to stray into human habitations frequently.
Since the formation of the state, 400 persons have fallen prey to leopards. The wildlife authorities, despite their best efforts, have failed to curb the increase in the fatal animal attacks on humans.
The coming months will be more challenging for the wildlife authorities as rains increase vegetation growth and thickens bushes and foliage, thereby, providing adequate cover to prowling leopards.
This video shows one waterspout in the gulf taken by a fishing-charter captain.












Comment: You can't really fault the bear for wanting to escape from what is essentially prison, with the added bonus of having people arrive every day to watch your every move. Looks like this bear decided enough was enough.