US West prepares for more days of record-breaking heat

By Tyler Clifford

(Reuters) - The western part of the United States is sweating through another round of record-breaking heat as a wave is forecast to produce triple-digit temperatures in cities from Southern California to northern Idaho through the middle of the week.

Some 30 million people are under heat advisories or excessive heat warnings in effect through Wednesday, with some projections topping 110 degrees Fahrenheit (43 Celsius), the National Weather Service (NWS) said on Sunday. Those states include parts of California, Arizona, Nevada, Idaho, Oregon and Washington.

Central Oregon and parts of Washington are also under elevated threats of wildfires due to hot and dry weather conditions, the NWS said.

Firefighters are battling multiple wildfires in Oregon, including the Lone Rock Fire that has scorched more than 116,000 acres (470 square kilometers) in the northern part of the state, according to the Oregon State Fire Marshal. About 40% has been contained. Thunderstorms moving through the state could make the response more difficult, officials said.

The Malheur County Sheriff's Office on Saturday ordered some residents to evacuate due to the Durkee Fire spreading in the eastern part of Oregon. In western Canada, wildfires in Alberta and British Columbia also forced evacuations over the weekend.

Research shows fossil fuel-driven climate change is helping to produce dangerous heat waves across the world. Officials are warning of major health risks associated with extreme heat, including heat stroke.

"At least for the next four days it looks pretty hot across a good part of the western U.S., and at least in the next two days there's definitely potential for some record high temperatures across parts of interior Pacific Northwest and down towards the desert southwest," NWS meteorologist Bob Oravec said.

The northwest part of the U.S. will experience the largest weather anomalies, including much of Washington state where temperatures are 20 degrees higher than usual this time of year, according to Oravec. Major cities like Seattle and Portland will be spared the extreme heat.

Temperatures are forecast to climb above 100 F (38 C) and break records in cities like Yakima, Spokane and Mack in Washington. Boise, Idaho could tie a record of 107 F (42 C), Oravec said.

Much of the West Coast will see temperatures that are about 10 degrees above normal. Las Vegas could tie a record of 113 F (45°C) on Sunday, while Death Valley National Park in California is expected to rise above 120 F (49 C).

"For Monday, the records drop off, like the potential to break records, but it doesn't mean it's going to be any significantly cooler. They're still going to be well above average across the same general areas," Oravec said.

On Saturday, records were broken in Baker, Oregon and Alturas, California, Oravec said.

(Reporting by Tyler Clifford in New York City; Editing by Mary Milliken and Chris Reese)