The extreme heat is expected to affect millions, particularly in densely populated areas of California, Nevada, Oregon, and Washington. Vulnerable groups, including the elderly, children, and those without access to air conditioning, face heightened risks of heat-related illnesses such as heat exhaustion and heat stroke. Outdoor workers and individuals engaging in strenuous activities are also at risk. The NWS has highlighted the dangers of cold-water shock for those swimming in rivers and lakes, which remain deceptively cold despite the high air temperatures. Prolonged heat can also strain power grids and increase the likelihood of wildfires in the region.