Hundreds of firefighters backed up by aircraft were battling a wildfire burning out of control for the third day on the eastern Aegean island of Chios Tuesday, with authorities issuing multiple evacuation orders.

Towering walls of flames tore through forest and agricultural land on the island, where authorities have declared a state of emergency and have sent firefighting reinforcements from Athens, the northern city of Thessaloniki and the nearby island of Lesbos.

The first heat wave of the year is hitting many parts of Western Europe, especially in the U.K. and France, where officials have issued health warnings.

People are covering up, using hand-held fans and seeking shade, or going for dips in the ocean and in fountains.

Tens of millions of people across the Midwest and East endured dangerously hot temperatures again on Sunday as a sprawling June heat wave that gripped much of the U.S. was expected to last well into this week.

Most of the northeastern quadrant of the country from Minnesota to Maine was under some type of heat advisory. So were parts of Arkansas, Tennessee, Louisiana and Mississippi, the National Weather Service said.

Greek authorities sent new evacuation notifications for two areas near the main town of the eastern Aegean island of Chios Monday morning, as firefighters struggled to control a major wildfire raging on the town's outskirts for a second day.

The fire department said 190 firefighters were battling the blaze Monday. They were backed up by 35 vehicles, five helicopters and two water-dropping planes. Strong winds in the area since Sunday have hampered firefighting efforts.

British health officials are warning people across the country to take precautions when out in the sun as the U.K. bakes under its first heat wave of the year.

Temperatures are expected to peak at 34 degrees Celsius (93 degrees Fahrenheit) in some parts of eastern England on Saturday following a week of unusually warm weather, according to the national weather agency the Met Office. That's about 12 C (22 F) higher than normal for this time of year.

Heavy rains have killed at least two people in Brazil 's southern region Rio Grande do Sul, the state's civil defense agency said on Wednesday, just over a year after the region was hit by record-breaking floods.

A 65-year-old man is also missing and more than 2,600 people have been forced to flee their homes, the agency added.

Humans are on track to release so much greenhouse gas in less than three years that a key threshold for limiting global warming will be nearly unavoidable, according to a study to be released Thursday.

The report predicts that society will have emitted enough carbon dioxide by early 2028 that crossing an important long-term temperature boundary will be more likely than not. The scientists calculate that by that point there will be enough of the heat-trapping gas in the atmosphere to create a 50-50 chance or greater that the world will be locked in to 1.5 degrees Celsius (2.7 degrees Fahrenheit) of long-term warming since preindustrial times. That level of gas accumulation, which comes from the burning of fuels like gasoline, oil and coal, is sooner than the same group of 60 international scientists calculated in a study last year.

Summer will make a dramatic entrance in the U.S. this week with a heat dome that will bring stifling temperatures and uncomfortable humidity to millions.

The heat will be particularly worrisome this weekend across wide stretches of Nebraska, Illinois, Wisconsin and Iowa, where forecasters are warning of extreme temperature impacts.

South Africa was under a declared state of national disaster on Thursday as the death toll from floods caused by severe rains in the Eastern Cape region rose to 92.

The Eastern Cape government honored the victims of last week's floods with a provincial Day of Mourning and a memorial service at King Sabatha Dalindyebo Technical and Vocational Education and Training (TVET) College in Mthatha, one of the few schools whose infrastructure remained intact.

Rescue workers used rubber dinghies to evacuate people and deliver food and water Wednesday after floodwaters overwhelmed towns in southern China's Guangdong province.

About 30,000 people have been evacuated in Huaiji County after days of heavy rain, state broadcaster CCTV said.