Earliest-ever heat wave in Greece closes Acropolis and public schools

A sweltering heat wave in Greece, recorded as the season's earliest-ever, has prompted authorities to close public schools, limit outdoor attractions and release safety alerts.

Primary schools and kindergartens closed Wednesday and Thursday in areas of Greece where temperatures sustained heat wave levels and soared well over 100 degrees Fahrenheit (exceeding 40 degrees Celsius) across the country, according to officials.

The Greek Climate Crisis and Civil Protection Ministry sent out a notice about the heat, and the decisions were made with the regional authorities and the municipalities.

Schools are set to reopen on Friday, which marks the last day of the academic year for many public schools in the country, officials said.

The Athens Acropolis, the capital city's most-visited tourist attraction, limited hours of operation on Wednesday and Thursday, closing the site from noon through 5:00 p.m. local time.

"This heat wave will go down in history," Panos Giannopoulos, Greece's state TV meteorologist, said during a Wednesday broadcast, according to The Greek Herald.

"In the 20th century, we never had a heat wave before June 19. We have had several in the 21st century, but none before June 15," he said.

The unprecedented early-season heat wave comes amid a 59-year-old American hiker's disappearance on the Greek island Amorgos. Albert Calibet, a former LA Sheriff's Department deputy, was hiking from Aegiali toward Katapola, which takes roughly four hours.

Calibet reportedly began his hike at 7 a.m. local time on Tuesday and was last seen at 11 a.m. by walkers he met with on a trail, according to Hellenic Police.

"Our thoughts and prayers are with Deputy Calibet's family and friends and our hope is that we can bring him home safely," said Los Angeles County Sheriff Robert Luna."We are actively collaborating with multiple agencies abroad to provide assistance in the search for Deputy Calibet and will use every resource we have available to bring him back to those who love him."

Heat waves, or heat and hot weather that can last for several days, can have a significant impact on society, including a rise in heat-related deaths, according to the World Health Organization (WHO).

Heat waves are among the most dangerous of natural hazards, but rarely receive adequate attention because their death tolls and destruction are not always immediately apparent, according to the agency.

From 1998-2017, more than 166,000 people died due to heat waves, including more than 70,000 who died during the 2003 heat wave in Europe, according to the WHO.