People in San Francisco and elsewhere in California experienced a deep orange sky on Wednesday as massive wildfires filled the air with smoke and cinders.
Skies were so dark it appeared more night than day at times, while in some places ash fell like snow.
Dark skies blocking the sun lowered temperatures at what has historically been the warmest time of year in San Francisco.
“Geo-color imagery shows a very thick multilevel smoke deck over much of California,” the US National Weather Service said in a tweet.
“This smoke is filtering the incoming energy from the sun, causing much cooler temperatures and dark dreary red-shifted skies across many areas.”
What were being described as “unprecedented” wildfires, fuelled by strong winds and searing temperatures, were raging across a wide swath of California, Oregon and Washington state on Wednesday, destroying dozens of homes and businesses in the western US states and forcing tens of thousands of residents to evacuate.
Hundreds of homes have been lost to massive Oregon wildfires with a potentially historic number of deaths feared in the northwestern US state, governor Kate Brown said on Wednesday.
More than 121,000 hectares (300,000 acres) are burning across Oregon including 35 major wildfires, with at least five towns “substantially destroyed” and mass evacuations taking place.
Along with neighbouring California and Washington states, Oregon has been scrambling to contain rapidly spreading wildfires since the weekend due to unprecedented heatwaves followed by intense, dry winds.