UPDATE: Photos Of Sinkhole Big Enough To ‘Fit Volkswagen Or 2’ In Burien
UPDATE 5/19/11 11:30 a.m.: Workers spent most of Thursday morning (May 19) uncovering a sinkhole that was discovered Tuesday during grinding work at the intersection of Ambaum Blvd. SW and SW 152nd.
The B-Town Blog’s Scott Schaefer and Mark Neuman dropped by around 10 a.m., and found out firsthand some interesting information about the potentially-dangerous discovery:
- Workers said there was an “unusual amount of sand” where the sinkhole was. “We usually don’t see this much sand,” said one.
- According to Steve Botkin from the City, the sinkhole measures around “6 feet deep by 20 feet by 8 feet wide.” Workers had marked the cement above it with orange spray paint to indicate its approximate location.
- Workers said that the next step is for Engineers to examine it before taking any action.
- It is still unknown what caused the sinkhole, but one can imagine that a large pocket of sand, some water, and road vibrations could have contributed to its formation just under the road.
“They say they will fill and repair today,” added Botkin. “No one around here knows the history of this…everyone was surprised, although there was some speculation about Burien’s rumored underground railway.”
Here’s an audio soundbite recorded at the scene:
Here are some pics taken on the scene Thursday morning:
Construction workers grinding Ambaum Blvd. SW Tuesday night (May 17th) apparently uncovered a sinkhole “that would fit a Volkswagen or two” where the street intersects with SW 152nd Street, according to a note on the city’s website.
“No one was aware of the sinkhole until top layers of pavement that are being grinded in preparation for resurfacing began to sink into the large hole,” reads the statement on the city’s website. “The hole was covered with steel grates and will be filled and paved on Thursday. Some traffic on SW 152nd St. and Ambaum will be diverted away from the intersection while the repair work takes place Thursday.”
We saw no obvious evidence of the sinkhole ourselves late Wednesday afternoon, although there is a large swath of freshly-laid asphalt in the intersection that may be serving as a temporary cover.
Here’s more info from the city:
The contractor began laying asphalt on Ambaum Blvd. SW on May 9th. As of Wednesday (May 17), the section of Ambaum between SW 112th and SW 126th streets had been completed. Grinding work and paving continues the week of May 17, moving south from S.W. 126th St.
During the nighttime repair work along Ambaum, traffic is being channeled and also detoured in some areas. No parking will be allowed on the street and driveway access may be temporarily affected during these times. Use of alternate routes such as 4th Ave. SW is recommended.
Asphalt laying had been delayed because of the wet weather, although the contractor is ahead of schedule. Rain also has been causing delays in the grinding process since wet pavement prevents lanes from being clearly marked.
What causes a sinkhole?
According to Wikipedia, a sinkhole is:
…a natural depression or hole in the Earth’s surface caused by karst processes — the chemical dissolution of carbonate rocks or suffosion processes for example in sandstone.
Sinkholes may vary in size from 1 to 600 meters (3.3 to 2,000 ft) both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. Sinkholes may be formed gradually or suddenly, and are found worldwide.
Sinkholes may capture surface drainage from running or standing water, but may also form in high and dry locations.