The Multnomah County Medical Examiner’s Office reported Monday that it’s looking into four possible heat-related deaths between Friday and Sunday.

A crew member wets a rag in a mist stream at the Waterfront Blues Festival in downtown Portland, Ore., July 6, 2024. In response to the heatwave, the festival set up free misting and water bottle filling stations, as well as allowing people to bring in personal umbrellas.

A crew member wets a rag in a mist stream at the Waterfront Blues Festival in downtown Portland, Ore., July 6, 2024. In response to the heatwave, the festival set up free misting and water bottle filling stations, as well as allowing people to bring in personal umbrellas.

Anna Lueck / OPB

The sweltering heat blanketing Oregon and Southwest Washington appears to have caused four deaths since Friday.

On Monday, the Multnomah County Medical Examiner’s office reported it is looking into three possible heat-related deaths of county residents.

The first suspected heat-related death was reported on Friday, July 5, when a man was found dead in the Cully neighborhood. Two more deaths were reported on Sunday: One man was found dead in the Mt. Scott area and another was found in the Hazelwood neighborhood.

Additionally, on Saturday, July 6, a man from outside of Multnomah County died from a suspected heat-related illness after he was taken to a Portland hospital.

Nearly all areas of Oregon and Southwest Washington are expected to remain under excessive heat alerts through at least Tuesday night. Gov. Tina Kotek declared a state of emergency for all of Oregon last week.

Related: Excessive heat lingers in Oregon and Southwest Washington

Temperatures soaring into the triple digits has historically been rare in Oregon. But the latest heat wave is part of a warming trend tied to human-caused climate change that has been more evident in the past four years.

The National Weather Service says temperatures are expected to peak Tuesday when highs could reach 105 degrees in the Willamette and Hood River valleys.

Officials are not releasing any additional details about the four men’s deaths. They added that the causes of death are preliminary and more tests are needed to confirm.

Heat-related illnesses are among the leading causes of death related to extreme weather. In 2021, 96 people died in a heat wave extending across the state. Most of those people lived in Multnomah County.

According to officials in Benton, Clark, Clackamas, Linn and Washington counties, no other suspected heat-related deaths have been reported so far.

This story will be updated.

Related: Pacific Northwest heat wave was a freak, 10,000-year event, study finds