(CNN) The searing heat that has baked the Northwest is suspected to have led to at least 14 deaths in Oregon and eight in Washington state, officials said.
The most recent death in Oregon was reported Saturday.
An "elderly male who died was in his home that had a non-functioning air conditioner," Clackamas County said in a news release. The medical examiner's office is investigating the official cause of that death.
Other suspected heat-related deaths happened in Multnomah, Clackamas, Umatilla and Marion counties, Oregon State Police spokesperson Mindy McCartt said.
The official causes of those deaths are also under investigation, McCartt said.
The temperature at Portland International Airport reached or exceeded 95 degrees for "6 straight days, with 3 of those at or just above 100," the National Weather Service said Saturday.
In Washington, there were seven suspected heat-related deaths since last week, the State Department of Health said in a statement on Tuesday, citing preliminary data.
At least three of those deaths occurred in King County, which includes Seattle, between July 26 and 31, the county medical examiner's office said in a separate news release.
During a 7-day period that ended Sunday, emergency rooms treated more than 540 patients with heat-related illnesses, the health department statement added.
More than 13 million people across the Northwest were under heat alerts Sunday, CNN meteorologist Haley Brink said. Major cities impacted include Portland; Seattle; Billings, Montana; and Boise, Idaho.
Much of the central and eastern regions of Washington and Oregon remained under excessive heat and red flag warnings Monday evening, according to NWS.
But the heat wave scorching the Northwest will ease up this week.
The most extreme temperatures have shifted away from the coast and into interior portions of the Northwest, Brink said Sunday. "This dome of heat will shift into the northern Plains by Tuesday and into the Midwest by Wednesday," she said. "And even the Northeast will get into above average temperatures by Thursday and Friday."