What are some of the challenges with assessing risk when constructing a building. In other words, what risks can be assessed up front, and what risks are examples of “unknown-unknowns”? Driving a car in London just got a lot more dangerous.

A soon-to-be-completed skyscraper in the downtown area is having an impact that no one could have imagined:

it is starting fires and melting cars. The building—

designed by internationally renowned architect Rafael Viñoly—is a dramatic edifice with curved exterior walls.

Built at 20 Fenchurch Street in London’s financial center, the 38-story skyscraper is known locally as “the Walkie-

Talkie” for its unusual shape.

But that curvilinear shape is exactly what’s causing the problem. The south-facing exterior wall is covered in reflective glass, and because it’s concave, it focuses the sun’s rays onto a small area, not unlike a magnifying glass directing sunbeams into a superhot pinpoint of light.

The beam caused by the curved skyscraper concentrating the sun’s rays was measured at more than 110 degrees Celsius (230 degrees Fahrenheit) in September.

So far, the building has been responsible for partially destroying a parked Jaguar XJ luxury car, catching carpets on fire in nearby shops, and shattering slate tiles at local restaurants. This is likely to be a recurring problem for any structure built within range of the powerful reflected light coming from the building.

Because the effect is caused by the sun’s elevation in the sky at certain times of the day and during a specific time of the year, experts expect the intense light and dangerous heating effect will last about two hours a day over a period of three weeks. To help in the short term, the building’s owners have contracted with local authorities to block off a limited number of parking spaces that are right in the reflected beam’s path.

Longer-term solutions are more problematic; the design of the building will not change and of course, the sun’s path is not likely to alter in the near future!

Melting cars and causing fires are not the only problems that have been reported because of the unique building design. In fact, it appears that the Walkie-Talkie building has a residual feature—the ability to blow people away. The 37-story building has a downdraft wind problem caused by its shape, and during breezy days, it has almost blown pedestrians into the road and has regularly toppled food carts parked along the street. In fact, this phenomenon has led city planners to revise the guidelines for building design and insist that independent wind studies be conducted on future building projects during their planning phase.

This isn’t the first time Viñoly’s architecture has been the subject of similar controversy. His Vdara Hotel in Las Vegas has been criticized for directing sunbeams onto the swimming pool deck that are hot enough to melt plastic and singe people’s hair. The technical term for the phenomenon is a solar convergence, but the hotspot soon became known as the “Vdara death ray.”

The Vdara resolved the death ray effect with larger sun umbrellas, but fixing the problem in London might take a lot more work. “There are examples in the past where an architect has had to rebuild the façade,” said Philip Oldfield, an expert in tall buildings at the University of Nottingham’s Department of Architecture.

“If this is serious, then I dread to think how expensive it will be.”