The Larimer County Sheriff's Office ordered mandatory evacuations Monday for a wildfire near Storm Mountain, west of Loveland, that quickly grew to hundreds of acres. The fire is being called the Alexander Mountain Fire. The U.S. Forest Service said a plane flew the area and the fire is about 864 acres and growing. They say it is burning in the Roosevelt National Forest. Earlier, Larimer County Sheriff's Office estimated the fire was larger than the Forest Service's assessment, but they are now following the Forest Service's estimate. The fire is 0% contained and the cause is undetermined, according to the USFS. Read more: https://www.9news.com/article/news/local/wildfire/wildfire-loveland-evacuations-colorado/73-15d780a8-b4e0-4a00-8e0c-dad82a1d5c2f More local videos here: https://youtube.com/@9news Subscribe to NEXT: https://youtube.com/@Nexton9NEWS Stay connected: 9NEWS Website: https://www.9news.com/ Facebook: https://www.facebook.com/ilike9news Twitter: https://twitter.com/9NEWS Instagram: https://www.instagram.com/9newsdenver/ Download the 9NEWS App: https://www.9news.com/appredirect/ Sign up for the 9NEWSLETTER: https://www.9news.com/email 9NEWS (KUSA) is located in Denver, Colorado.