Hundreds of people died in the western US heat wave last week. And now another is brewing

(CNN) – The relentless heat is expected to continue in the western United States after the late June wave that killed hundreds in the Pacific Northwest and British Columbia. Records could be set again this weekend as temperatures rise well above normal.

The number of Oregonians who died from heat-related illnesses during the historic wave in late June rose to 107, the state medical examiner said in an updated statement Tuesday. While deaths were reported statewide, nearly two-thirds occurred in Multnomah County, where the city of Portland is located.

Many of those who died were found alone, without air conditioning or a fan, county officials said.

The number of deaths is higher than in previous years. Between 2017 and 2019, 12 deaths were reported statewide from hyperthermia, which is when the body overheats, authorities had previously reported.

At least 13 deaths are attributed to this heat wave in the Seattle area. And in British Columbia there were 486 sudden deaths during the wave, almost triple the usual number, the coroner’s office said. The country broke the record for the highest temperature in history.

Oregon Gov. Kate Brown said Sunday that the “horrifying” heat wave is “a harbinger of things to come” as climate change intensifies extreme weather conditions and drought. Brown said the state is conducting a review of its response to the deadly heat wave and requested support from the federal government for wildfire prevention efforts.

The prolonged and unprecedented heat is getting worse and more frequent due to climate change, experts told CNN.

Increase in temperatures in the middle of the week

A week later, a high pressure ridge is strengthening again in the west on Tuesday and Wednesday, with temperatures set to exceed 37 degrees later in the week.

“Excessive and oppressive heat will continue for at least the first half of the week in the Northwest, where daytime highs will rise to between 35 and 40.5 degrees Celsius, according to the Weather Forecast Center. “All-time daily highs, once again, could be broken Tuesday and Wednesday in parts of the Great Basin and Northern California.”

Eastern Oregon, Nevada and Idaho could set daily high temperature records again as daytime temperatures reach around 38 degrees Celsius.

“This will bring near record temperatures and could possibly be the hottest day of the year so far,” said the National Weather Service in Boise (NWS).

Boise has already had a hot week. It broke the record for the longest streak of lows above 21, which was held for nine trackers days, breaking the previous record of five days in 2015, according to the NWS.

These hot lows are combined with a seven-day streak of high temperatures of more than 37.8 degrees. Boise is forecast to hit 37.8 in the next three days, breaking the record for a run of nine days with temperatures above that number.

If your wondering how many consecutive days of Max Temperatures of 100 F or greater in #Boise, as of July 4th, it’s been 7 days. We could break the all-time record of 9 days on Wednesday which is currently forecast to reach 101 F. #idwx #orwx pic.twitter.com/NX0UIOzYvw

– NWS Boise (@NWSBoise) July 5, 2021

Current Heat Warnings

Excessive heat advisories are in effect for much of eastern Oregon and western Idaho on Tuesday, which will be in effect through the evening.

Northern Nevada, Northern California, and Southern Oregon have heat advisories in effect. There the temperatures will be above 37.8 degrees.

The NWS in Pocatello, Idaho, says there are likely to be more heat alerts and warnings for southern Idaho on Tuesday. Red flag warnings are also in effect for Friday, when temperatures begin to rise again, with the possibility of scattered thunderstorms that in turn raise the risk of wildfires.

The heat will peak on Tuesday and Wednesday in most of the region. On Thursday a front will ease the area: temperatures will continue to be above average, but closer to normal values.

After Thursday, the heat will increase towards the weekend in some parts of the west.

Worrying heat wave on the weekend

Another high pressure ridge centered over Nevada will begin to form at the end of the week and into Saturday, and daily highs will shoot back above 37.8 degrees.

“The coastal range along the Great Basin to the northern Rocky Mountains would record highs of 5.5 to 8 degrees Celsius above normal every day, with higher temperatures possible locally. Various daily records of Maximum temperatures could be exceeded again every day, mainly in the Great Basin, with a slight movement west to California this weekend as the axis of the ridge shifts to the west, “said the WPC.

The new 6 to 10 day temperature outlook builds more heat across the interior NorCal region with next weekend trending very hot. #cawx #caheat pic.twitter.com/zT5H9Zusez

– NWS Sacramento (@NWSSacramento) July 5, 2021

In eastern Washington, Oregon and Idaho, records for daily highs could be broken again this weekend. Maximum temperatures in Northern California will also rise, surpassing 37.8 degrees Celsius and in some cases even 43.

“Notably, the latest national mix of models (for weather forecasting) already gives Redding a 60% and 73% chance of exceeding 43 degrees on Saturday and Sunday next weekend respectively. Redding already 10 consecutive days at or above 37.8 degrees, and it looks like we will easily add at least eight more days to the current streak, “said the NWS in Sacramento, California.

This summer has already proven to be scorching for the west. Drought conditions have worsened, and fire-prone weather is making large fires significantly worse in places like California. Smoke over the Great Basin from the California fires will cause annoyance throughout the week.

California fires

Multiple large fires are burning in Northern California, including the Salt and Lava fires that swept over 12,000 acres, according to InciWeb, they’re burning in Northern California. Smoke from the fire is impacting areas of southern Washington and western Idaho.

The monsoon humidity this weekend has proven helpful for Arizona and New Mexico, but left the regions that need it most in the Northwest dry.

The weekend heat wave is expected to last into the next week. Prolonged heat conditions with little relief overnight sets the stage for another dangerous week in the west.

CNN’s Jon Passantino contributed to this report.