Just a few weeks ago, scientists announced to the world the existence of the largest ozone hole ever documented in the Arctic that measures about 1 kilometer in diameter. Now, the hole has closed almost as quickly as it formed.

Experts believe that the hole was formed earlier this year and reached its maximum size in March due to the unusually cold winter temperatures. It quickly disappeared again just as it formed because of the unexpectedly warm spring temperatures.

Recap on what caused the largest ozone hole

Earlier this month, Science Times reported the record-size hole in arctic that measures up to 1 kilometer in size. The Copernicus' Atmospheric Monitoring Service and some researchers believed that the sudden growth of the hole was caused by an usually strong polar vortex, according to a report in CNN.

The polar vortex is a high altitude current that helps keep cold air trapped above the pole as it travels in an irregular ring-like pattern around the Arctic.

Lower temperatures in the North Pole dropped so much enough to cause the formation of the polar stratospheric clouds (PCS), which activates ozone-depleting chemicals such as chlorine in the atmosphere.

The hole in the North Pole is rather unexpected as its temperatures are not quite as cold as those in Antarctica. This makes the seasonal appearance of ozone holes in the Arctic rare, while it is commonly observed in the south.

Corpenicus' Antje Inness told Euro News, "it is very unusual for such strong ozone depletion to occur in the northern hemisphere, but this year's polar vortex was exceptionally strong and persistent, and temperatures were low enough to allow stratospheric cloud formation for several months."

When holes appear on the ozone, it means more harmful solar radiation is penetrating the atmosphere and reaching the Earth's surface as ozone helps filter ultraviolet light from the atmosphere.

So, why did it closed?

The disappearance of the ozone hole has made headlines just weeks after its existence was first announced. Some suggested that it disappeared due to the radical reductions in air pollution during the worldwide COVID-19 shutdowns but the CAMS team have rejected the idea and offered another explanation.

The group wrote in a Twitter post that, "COVID19 and the associated lockdowns probably had nothing to do with this,' the group wrote in a Twitter post. It's been driven by an unusually strong and long-lived polar vortex, and isn't related to air quality changes."

The team said that its disappearance is likely a result of the polar vortex warming, which then mixes to the ozone-rich air from the lower atmosphere, in which it offsets the temporary depletion of the ozone.

While the winter months have driven the polar vortex into unusually low temperatures, the researchers hole's dissipation is due to what they describe as a "heat wave" with temperatures as much as 36 degrees Fahrenheit warmer than the usual.

The heat wave caused the polar vortex to shrink into two smaller and separate vortices, reported by MailOnline.