Hot Topic: A Systematic Review and Content Analysis of Heat-Related Messages During the 2021 Heat Dome in Canada

Abstract

Context: During the summer of 2021, western Canada experienced a deadly heat event. From the first heat alert to postevent reporting, thousands of media articles were published that reference the heat event. However, a gap remains in understanding how this communication chain-from the release of a public heat alert to information shared through media outlets to the public-currently operates to disseminate heat-related messaging across Canada.

Objective: To understand the role of digital media in delivering heat-health messaging during an extreme heat event in Canada.

Design: A qualitative content analysis was conducted using Canadian news articles published on the 2021 Heat Dome between June 2021 and February 2022 (n = 2909). The coding frame was designed to align with the basic framework for information gathering used in journalism (who, what, where, when, and how) and included both concept-driven and data-driven codes.

Results: Overall, 2909 unique media articles discussing the 2021 Heat Dome were identified, with the majority (74%) published by online news agencies (how). The highest article count was on June 29, 2021 (n = 159), representing 5% of the total data set (n = 2909) spanning 260 days (when); 57% of the identified locations were in British Columbia (where). Although we found that the top voices providing media-based heat-health messages are government officials (who), only 23% of articles included heat-health messaging that aligns with the government health alert bulletins released during extreme heat. In addition, heat-health messaging frequently included contradictory content, inconsistent language, or incorrect advice (what).

Conclusion: The findings demonstrate clear opportunities to improve health communication related to extreme heat, perhaps most importantly, including updates to mass media messaging educating the public on heat-protective behaviors.

FIGURE 1

Sources of News Articles on the 2021 Heat Dome (HOW)^{a a}The number of novel digital news articles related to the 2021 Heat Dome is categorized by type of source. The shading corresponds to the number of articles from each source, with dark shades (black/dark gray) indicating categories with a greater number of articles and light shades (light gray) indicating fewer articles.

FIGURE 2

Timeline of News Publications on the 2021 Heat Dome (WHEN)^{a a}Panel A: number of digital news articles on the 2021 Heat Dome published each week during the entire study period (June 1, 2021 to February 26, 2022). Panel B (inset): number of digital news articles published during the Heat Dome (June 24 to July 7). For both panels, the shading of the bars corresponds to the weekly (panel A) or daily (panel B) number of articles published, with dark shades (black/dark gray) indicating a greater number of articles published and light shades (light gray) indicating fewer published articles. The gray dotted line on each panel indicates the cumulative number of articles published over each period.

FIGURE 3

Map of the Digital News Articles Published on the 2021 Heat Dome (WHERE)^{a a}Panel A: References to Canadian provinces/territories in digital news articles. The shading corresponds to the number of times each province/territory was referenced in each category, with dark shades (black/dark gray) indicating a greater number of references and light shades (light gray) indicating a smaller number of references. Panel B: References to specific locations in western Canada, including cities, counties, districts, First Nations, hamlets, islands, lakes, municipalities, rivers, towns, townships, unincorporated communities, and villages. The size of each bubble indicates the number of times each location was referenced, ranging from less than 10 (eg, n = 1, Tadoule Lake, Manitoba; small light gray dots in upper right portion of map) to more than 640 (n = 651, Lytton, British Columbia; large black point in lower left corner). The shading of the points indicates the density of location references, considering both the number of times each location was referenced and its geographical relation to other referenced locations. Dark shades (black/dark gray) indicate a greater density and light shades (light gray) indicate a lower density.

FIGURE 4

Voices Cited in News Coverage Related to the 2021 Heat Dome (WHO)^{a a}Panel A: Number of cited voices in each category among digitized news coverage related to the 2021 Heat Dome by category. The shadings in Panel A correspond to the number of voices in each category, with dark shades (black/dark gray) indicating categories with a greater number of voices and light shades (light gray) indicating categories with fewer voices. Panel B: Regional affiliation of each voice. The shadings in panel B indicate affiliation groupings (see legend).