ISLAMABAD (AP) — Authorities in Pakistan on Tuesday urged people to stay indoors as the country is hit by an extreme heat wave that threatens to bring dangerously high temperatures and yet another round of glacial-driven floods.

Pakistan’s most populous province, Punjab, is shutting all schools for a week because of the heat, affecting an estimated 18 million students.

“The sweltering heat will continue this month,” said Zaheer Ahmed Babar, a senior official at the Pakistan Meteorological Department. He added that temperatures could reach up to 6 degrees Celsius (10.8 Fahrenheit) above the monthly average. This week could rise above 40 degrees Celsius (104 Fahrenheit) in many parts of the country, Babar said.

It’s the latest climate-related disaster to hit the country in recent years. Melting glaciers and growing monsoons have caused devastating floods, at one point submerging a third of the country.