Pacific Northwest braces for ‘hazardous heat’

The Pacific Northwest is facing a particularly grim outlook when it comes to brutal summer heat, federal weather experts said on Thursday. 

Over the next two weeks, meteorologists are “favoring above normal temperatures at pretty high odds for much of the western part of the lower 48, with the highest odds across the Pacific Northwest region or the Rockies,” according to Jon Gottschalck, chief of operational predictions at the National Weather Service’s Climate Prediction Center.

The situation is expected to become especially dire for the Pacific Northwest, including the cities of Portland and Seattle, which could experience “hazardous heat,” Gottschalck warned. He spoke at a U.S. Drought and Heat Webinar hosted by the National Integrated Drought Information System and National Integrated Heat Health Information System — branches of the National Oceanic and Atmospheric Administration (NOAA).

As the U.S. West encounters its driest megadrought in at least 1,200 years, driven by climate change, regional reservoirs are reaching record lows and wildfires began raging early in the season.

“All the indicators are showing now that the current drought is one of the most severe in the last several thousand years,” said David Simeral, a research scientist at the Nevada-based Desert Research Institute and a national author for the U.S. Drought Monitor.

“At this point, looking at projections and so forth, it’s not looking like the situation is going to change in the near future,” Simeral continued. “It’s looking like we are in the middle of a megadrought and the situation could possibly be continuing for some time into the near future.”

At the moment, 73 percent of the Western U.S. is encountering drought, while 30 percent is in the most severe drought categories, according to Simeral. Looking at specific regions, he said that 99 percent of California is experiencing drought, as is 87 percent of the Intermountain West.

As the excessive heat conditions that have been scalding Southern California move into California’s Central Valley and into the Pacific Northwest over the next two weeks, these regions could experience “dangerous heat,” Gottschalck warned.

The heat index — or what the temperature feels like to the human body — will likely be greater than 105 degrees, he explained. 

On the other hand, Gottschalck countered, localized heavy rainfall associated with monsoon thunderstorms could provide some respite from Arizona into parts of southern Colorado.

Looking ahead into August, Gottschalck forecast “above normal temperatures again at high probabilities for much of the West,” with ongoing dryness stretching across parts of the central Rockies through October.

The La Niña weather system — which has created excessive heat in the West for the past two years — is expected to continue for the remainder of 2022, according to Gottschalck.

As far as accompanying wildfire activity is concerned, blazes are ongoing in Yosemite National Park and in Utah and Idaho, reported Jim Wallman, a senior forecaster for the National Interagency Fire Center.

“Through the rest of this month, we’re looking at moderate fire potential to continue for much of California, into the Great Basin in Northern Rockies, also for portions of the Inland Northwest,” Wallman said, noting that monsoon season will dampen such risk in the Southwest.

Due to the persistent high temperatures throughout the region, meteorologists are also concerned about potential lightning strikes and heavy winds, which could contribute to new fire starts but remain difficult to predict, according to Wallman.

Throughout August, he continued, much of California will experience above-normal potential for wildfires — a risk exacerbated by the long-term drought and resultant dry fuels.

The Great Basin and southeast Oregon rangelands, whose wet winters led to robust grass growth, will also face heightened risk of wildfires this August, Wallman added.

Looking toward a future of continued drought and excessive heat conditions, the scientists expressed concern about the connected health outcomes that Americans are facing.

“Extreme heat is the deadliest weather-related event in the United States,” said Sarah Kapnick, NOAA’s chief scientist.

Kapnick noted, however, that “all heat-related illnesses and deaths are avoidable” by making use of technological tools like drought early-warning systems and through cross-agency collaboration.

“Summers have been getting hotter, with July of 2021 registering as one of the hottest months ever recorded on Earth,” Kapnick said. 

“With the expectations of these trends to continue, another way to think about this is it was also one of the coolest summers of the rest of our lives,” she added.