Starting in May 2023, a

heat wave A heat wave or heatwave, sometimes described as extreme heat, is a period of abnormally hot weather generally considered to be at least ''five consecutive days''. A heat wave is usually measured relative to the usual climate in the area and ...

affected

Western North America Western North America is the western edge of the North American continent that borders the Pacific Ocean. It consists of Alaska at the farthest north, down through the western Canadian province of British Columbia, the western U.S. states of Wa ...

. The heat wave entailed wildfires in Alberta, record temperatures across Canada and the US, and over 100 deaths in Mexico. The heat also accelerated snow melt in mountain ranges, causing flooding and mudslides. According to scientists,

climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

increased the strength of the 2023 heatwaves including in North America.

Overview

Canada

The heat wave has fueled the

wildfires in Alberta A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a ...

Environment Canada Environment and Climate Change Canada (ECCC; )Environment and Climate Change Canada is the applied title under the Federal Identity Program; the legal title is Department of the Environment (). is the Ministry (government department), department ...

has issued heat warnings for the northern parts of

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

and parts of

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

. Environment Canada stated, "While the developing heat may result in daily temperature records being broken, it must be emphasized that the expected hot conditions will not approach those reached during the 'Heat Dome' of late June 2021". On May 13, the hamlet of

Arviat Arviat (, Inuktitut syllabics, syllabics: ᐊᕐᕕᐊᑦ; formerly called Eskimo Point until 1 June 1989) is a predominantly Inuit Hamlet (place)#Canada, hamlet located on the western shore of Hudson Bay in the Kivalliq Region of Nunavut, Canada ...

Nunavut Nunavut is the largest and northernmost Provinces and territories of Canada#Territories, territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the ''Nunavut Act'' and the Nunavut Land Claims Agr ...

reached , which was about higher than the previous May record. The next day,

Squamish, British Columbia Squamish (; , ; 2021 census population 23,819) is a community and a district municipality in the Provinces and territories of Canada, Canadian province of British Columbia, located at the north end of Howe Sound on the British Columbia Highway 99 ...

reached a record high temperature of , and Lytton and

Tofino Tofino ( , Nuu-chah-nulth language, Nuu-chah-nulth: ''Načiks'') is a town of approximately 2,516 residents on the west coast of Vancouver Island in the Provinces and territories of Canada, Canadian province of British Columbia. The District ...

set monthly records of and , respectively.

United States

On May 12, the

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

issued a health advisory between May 13 and 15 for the western parts of

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

and

Washington state Washington, officially the State of Washington, is a state in the Pacific Northwest region of the United States. It is often referred to as Washington State to distinguish it from the national capital, both named after George Washington ...

. On May 13, four locations in the

Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...

region broke temperature records, with Quillayute reaching , SeaTac reaching , and Olympia and Hoquiam reaching . On May 14, cities such as

Hoquiam, Washington Hoquiam ( ) is a city in Grays Harbor County, Washington, Grays Harbor County, Washington (state), Washington, United States. It borders the city of Aberdeen, Washington, Aberdeen at Myrtle Street, with Hoquiam to the west. The two cities share a ...

and

Florence Florence ( ; ) is the capital city of the Italy, Italian region of Tuscany. It is also the most populated city in Tuscany, with 362,353 inhabitants, and 989,460 in Metropolitan City of Florence, its metropolitan province as of 2025. Florence ...

, Oregon set monthly temperature records, with high temperatures of or above. Seattle reached the same day.

Eugene Eugene may refer to: People and fictional characters * Eugene (given name), including a list of people and fictional characters with the given name * Gene Eugene, stage name of Canadian born actor, record producer, engineer, composer and musi ...

and

Portland Portland most commonly refers to: *Portland, Oregon, the most populous city in the U.S. state of Oregon *Portland, Maine, the most populous city in the U.S. state of Maine *Isle of Portland, a tied island in the English Channel Portland may also r ...

reached and , respectively. The heat has caused the snow on some mountain ranges such as the

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

Colorado Rockies The Colorado Rockies are an American professional baseball team based in Denver. The Rockies compete in Major League Baseball (MLB) as a member club of the National League (baseball), National League (NL) National League West, West Division. Th ...

and

Cascade Range The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington (state), Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as m ...

to melt rapidly, posing danger due to flooding, mudslides and landslides. On May 14, flooding of the

Ogden River The Ogden River is a long river in Weber County. Utah, United States. Description The Ogden River's three forks (North, Central, and South) begin in the Wasatch Range in Weber County and converge at Pineview Reservoir, near Huntsville. Th ...

forced residents of

Huntsville, Utah Huntsville is a town in Weber County, Utah, United States. The population was 608 at the 2010 census. It is located in Ogden Valley. It is part of the Ogden– Clearfield, Utah Metropolitan Statistical Area, as well as the Ogden Valley c ...

to evacuate their homes, and part of State Route 504 near

Mount St. Helens Mount St. Helens (known as Lawetlat'la to the local Cowlitz people, and Loowit or Louwala-Clough to the Klickitat) is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States ...

Cowlitz County, Washington Cowlitz County is a county located in the U.S. state of Washington. As of the 2020 census, its population was 110,730. The county seat is Kelso, and its largest city is Longview. The county was formed in April 1854. Its name derives from th ...

, was destroyed by a mudslide off the Cascade mountains. In mid-June, more than 100 million individuals, or almost one-third of all Americans, were "under extreme heat advisories". On July 31,

Phoenix, Arizona Phoenix ( ) is the List of capitals in the United States, capital and List of cities and towns in Arizona#List of cities and towns, most populous city of the U.S. state of Arizona. With over 1.6 million residents at the 2020 census, it is the ...

ended a 31-day streak of high temperatures of over . The average temperature in Phoenix during July 2023 was , the hottest month for any U.S. city in history. On July 19, Phoenix broke their all time warmest low temperature by only falling to at night. The extreme heat resulted in 569 deaths in Phoenix. The summer heat wave resulted in

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

experiencing its second hottest summer on record in 2023, with the full year being its hottest on record. Over 300 people died from heat in Texas in 2023, the most since the state began tracking such deaths in 1989.

Mexico

Over 100 people died across Mexico as a result of two weeks of heat waves in the country.

References

{{Heat wave Heat waves in Canada Heat waves in the United States 2023 meteorology 2023 heat waves May 2023 in Canada May 2023 in the United States History of the Pacific Northwest

Overview

Canada

United States

Mexico

See also

References