A dangerous heat wave is expected to affect parts of the Pacific Northwest over the weekend in a region where authorities are still addressing the deadly impact of record-breaking temperatures in 2021.

The extreme heat could pose major health risks for people in parts of Washington, Oregon and Idaho who can’t rehydrate or get out of the heat, according to the latest guidance from the National Weather Service.

The Weather Service said on Friday that the heat is expected to intensify over the interior Pacific Northwest, possibly reaching as high as 110 degrees Fahrenheit in some locations. In Spokane Valley, Wash., the heat index could reach 104 degrees Fahrenheit on Sunday before a slight dip in the following days.

In northwestern Oregon, highs of 95 to 98 degrees are forecast for the Willamette Valley. “The average for this time of year is around 83 to 84 degrees,” said Hannah Chandler-Cooley, a Weather Service meteorologist. “So we are well above average. We have been above average since our heat wave early this month.”

Some areas in central and eastern Oregon could experience temperatures between 100 and 110 degrees from Saturday morning through Monday.

In Boise, Idaho, the combined heat and humidity will make it feel like the temperature is in the low 100s from Saturday through Monday. In Lewiston, Idaho, the heat index is expected to reach 100 degrees on Friday and 108 degrees on Sunday.