An unusually expansive outbreak of large and fast-moving wildfires threatens communities in three states Wednesday, with the greatest risks focused on Medford, Ore., and Oroville, Calif., as large fires advance in those areas.

In Oregon on Wednesday afternoon, Gov. Kate Brown (D) announced that four towns have experienced significant damage, and she warned residents to expect news of fatalities.

“Oregon has experienced unprecedented fire with significant damage and devastating consequences for the entire state,” she said. Brown said the communities of Detroit, Blue River, Vida, Phoenix and Talent are “substantially destroyed."

“Hundreds of homes have been lost."

The partial evacuation in Medford, which took place Tuesday night into Wednesday morning, was prompted by one of many new blazes that started Monday and Tuesday.

The wildfires come after a record-shattering heat wave and amid human-caused climate change that is heightening fire risks, along with temperatures, in the West. These blazes are being driven by strong, dry, offshore winds that are causing extreme fire behavior, which can produce everything from mushroom cloud-like plumes of smoke that reach 40,000 feet in height, to vortexes that make it impossible for firefighters to contain an advancing fire.

Here are some significant developments:

  • The Glendowner Fire (also known as the Almeda Fire) has prompted the evacuation of parts of Medford, Ore., a city of 82,000 people, where many fled their homes. Areas to the southeast of the city, including Phoenix, Ore., saw structures destroyed as the fire swept through the region Tuesday evening. At least one fatality has been reported with this fire.
  • Gov. Brown said more than 300,000 acres are burning across Oregon, and that this could be the deadliest wildfire disaster in state history.
  • “This event is unprecedented. I’ve talked to people who have been in fire for 20, 30, 40+ years and they’ve never seen anything like this before. Not this many large, rapidly spreading wildfires across such a broad region,” tweeted Nick Nausler, a fire weather specialist with the National Interagency Fire Center in Boise, Idaho.
  • The Bear Fire that began in a remote region of Northern California advanced rapidly about 25 miles through timber Tuesday evening through Wednesday morning, coming close enough to Oroville, Calif., to prompt evacuation warnings in the area as well as parts of Paradise, Calif. That’s the same town nearly destroyed in a deadly 2018 wildfire. The fire is part of a larger complex that has rapidly burned about 254,000 acres.
  • The U.S. Forest Service has taken the rare step of temporarily closing all national forests in California because of the high fire danger and ongoing blazes.