At least four firefighters have been injured over the last week while battling three wildfires in Northern California forests that are burning amid extreme heat in steep, bone-dry terrain, fire officials said Monday.

Two large wildfires in Northern California, one near Shasta Lake, continue to burn amid extremely hot weather, sending smoke throughout the state. The Green Fire and the Orleans Complex Fire have burned a combined 15,800 acres as of Sunday morning.

Heavy winds that swept through Black Canyon of the Gunnison National Park on Sunday night started “rapid fire spread” after a relatively slow day of growth, according to fire officials.

Greenhouse gas emissions, mainly from burning coal, oil and gas, have heated the planet by about 1.3 degrees Celsius since pre-industrial times. Europe has warmed at twice the global average since the 1980s, according to the World Meteorological Organization.

New York State Forest Rangers handled multiple emergencies across the state last week, including wildfires, wilderness rescues, and flood assistance, according to the Department of Environmental Conservation’s July 15 report.

Five wildfires are burning on thousands of acres in western Colorado, including one that crossed into the state from Utah, fire officials said Sunday.

Wildfire smoke has made its return to Central Oregon skies. As wildfires continue to burn around the region, many residents are waking up to hazy skies, air quality alerts and the lingering smell of smoke.