People across the East Bay are picking up after damage from this weekend's storm, including at the Oakland Zoo.
The zoo announced Sunday that the zoo itself and its popular Glowfari program are closing through at least Jan. 17 due to significant damage on the grounds from the storm.
Most notably, the zoo entrance at Golf Links Road is now entirely impassable because of a gaping hole in the ground which now has water rushing through it. The zoo is calling this a sinkhole, the deepest part of which they estimate to be 10 feet by 10 feet.
In a post on social media, the zoo said the hole is caused by "a collapsed culvert located under the vehicle entrance" which was "overburdened by the historic and unprecedented amount of rainfall throughout the region over the past few days." The zoo also noted this culvert connects the Arroyo Viejo Creek under the entry road.
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Oakland Zoo CEO Nik Dehejia put it bluntly, “This is not the way we wanted to start 2023.”
"The animals are safe at the zoo, that is the most important thing," Dehejia added.
While the zoo will be closed to the general public, staff will continue to go to the property to care for the animals, the zoo said.
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Dehejia explained that the zoo is already working with a company to make a plan for repairs. But incoming bouts of severe weather may delay that progress.
“We’ve got another atmospheric river event coming through this week, we have to let that rain get through us and see where they land, “ Dehejia said.
In addition to the large hole across the zoo entrance, the zoo has other erosion damage after this weekend's storm as well as some eucalyptus trees which have toppled.
"We do everything we can to make sure all of our drainage systems to make sure the soil is secure, but again, when you have this level of volume and velocity of water, there’s really nothing you can do, this is really unprecedented," Dehejia continued.
What's Going on in the Ground
Brian Collins, a research civil engineer with the USGS Landslides program, explained that while the hole at the zoo grounds may not fit the technical definition of a sinkhole, it is still significant.
“This may look initially like a sinkhole in that it could be circular or something like that, but it's revealed that it’s a stream crossing, and that’s the likely cause for what happened here,” Collins said.
Collins, who lives in the East Bay and has been to the zoo, said with the significant weather event the Bay Area experienced this weekend, he is not surprised to see erosion lead to this kind of damage. He noted that it is very common to see culverts collapse during a flood event and in this case he thinks the water flowing under the road probably eroded the road itself.
Collins also said that this is event gives yet another reason for Bay Area residents to heed local weather advisories -- and advisories for the hazards which come with severe weather.
"They can occur quite rapidly," Collins noted of erosion events.
Oakland geologist and writer Andrew Alden noted in an email to NBC Bay Area that the Hayward Fault runs through the zoo from north to south and intersects the road near the zoo entrance where the creek goes beneath the road.
"The culvert was several decades old and may have suffered from time and traffic," Alden said.
"But it's also quite possible that slow creep on the fault, which amounts to several millimeters per year, has added extra damage there to the point that the culvert failed under the exceptional stormwater running through it yesterday," he continued, adding that whatever replacement is installed should allow for the possibility of more slow creep on the fault.
Glowfari Cancellation and Refunds
At the zoo on Sunday night, dozens of people pulled up to the entrance expecting to attend the zoo's popular wintertime Glowfari event.
“People have been pulling up to the entrance of the Oakland Zoo all evening, many of them with Glowfari tickets.. only to be greeted with some disappointing news from zoo security.
Corene Carpenter and KDF Reynolds arrived at the zoo, only to learn from a security guard and a barricaded entrance they wouldn't be able to use their Glowfari tickets.
"I thought that if there was damage that they might let us know -- they might have time to let us know but I guess they didn’t,” Reynolds said.
"We had an outing all planned," Carpenter noted, "we're all dressed up with nowhere to go!"
Both were relieved to hear that the zoo animals are OK.
The zoo plans to refund everyone who had tickets to Glowfari during the days the zoo is closed.
Dehejia said those refunds should come automatically and that the zoo is working to email affected customers in the coming days.
"We are going to refund everybody who has a ticket and then we’re going to have to assess how long are we going to be closed," he said. "Maybe we can extend Glowfari, we’re talking to the company that puts it on for us about that."
Dehejia added that those with questions can reach out at tickets@oaklandzoo.org though he asked for patience from customers due to a high volume of requests.
