Exhibit 99.1 1 Contact: Media: Lena Funston (509) 495-8090 lena.funston@avistacorp.com Investors: Stacey Wenz (509) 495-2046 stacey.wenz@avistacorp.com Avista 24/7 Media Access (509) 495-4174 Avista Corp. Reports Financial Results for the Third Quarter of 2024 • Quarterly results demonstrate continued improvement at core utility from 2023 • Expect to be at the low end of Avista Utilities guidance range • Lowering earnings guidance for our other businesses due to lower than expected investment valuations | - ...