At an k index of 5: https://www.swpc.noaa.gov/products/alerts-watches-and-warnings https://www.swpc.noaa.gov/products/planetary-k-index

Edit: stormy pictures: https://www.esa.int/Science_Exploration/Space_Science/Live_view_of_the_Sun_from_SOHO

Video above Alaska: https://earthsky.org/sun/sun-news-activity-solar-flare-cme-aurora-updates/

At an k index of 5: https://www.swpc.noaa.gov/products/alerts-watches-and-warnings https://www.swpc.noaa.gov/products/planetary-k-index

Edit: stormy pictures: https://www.esa.int/Science_Exploration/Space_Science/Live_view_of_the_Sun_from_SOHO

At an k index of 5: https://www.swpc.noaa.gov/products/alerts-watches-and-warnings https://www.swpc.noaa.gov/products/planetary-k-index

At an k index of 5: https://www.swpc.noaa.gov/products/alerts-watches-and-warnings