Chase Woodruff/Colorado Newsline

Dozens of schools in Denver closed early again on Thursday, and several will remain closed all day, as a record-breaking fall heat wave continues to scorch much of Colorado and the western U.S.

Temperatures in the Denver metro area reached a record high of 99 degrees Fahrenheit and are forecast to rise nearly as high on Thursday before the high-pressure “heat dome” impacting many Western states dissipates this weekend.

Parts of both the Western Slope and the Eastern Plains recorded temperatures of 100 degrees or higher, also tying or exceeding all-time highs.

The record temperatures have led to Colorado’s first-ever heat advisory issued in the month of September and prompted early release schedules at facilities in the Denver Public Schools system that lack air conditioning. A full list of the impacted schools is available on the DPS website.

In 2019, DPS released a list of 55 schools that did not have air conditioning. A bond issue passed by Denver voters in 2020 provided $128.5 million to install air conditioning at 24 schools, but so far work has been completed at only six of them.

“This summer, nine schools were scheduled to have air conditioning installed, but, due to supply chain issues, eight schools are only partially completed,” DPS said in a press release. “That work is expected to be completed this fall.”

Denver officials estimate that about 30% of homes in the city lack air conditioning and have promoted the adoption of more efficient electric heat pumps to both adapt to rising temperatures and reduce greenhouse gas emissions.

All 30 of Denver’s recreation centers will be open as free cooling stations on Thursday, the city said.

No major outages or electricity shortages had been reported by Colorado utilities or power providers as of Wednesday night. Xcel Energy, the state’s largest electric utility, said on Tuesday that it was “encouraging customers to consider ways to save energy and keep their bills low,” suggesting steps like lowering blinds or curtains, using ceiling fans and making sure exterior doors are closed.

Fueled by global emissions of heat-trapping greenhouse gases, average temperatures in many parts of Colorado have risen by 4 degrees Fahrenheit or more since reliable record-keeping began in 1895, according to data from the National Oceanic and Atmospheric Administration.

Over the last 40 years, the continuing warming trend has been driven especially by higher temperatures in the fall months, according to a Colorado Climate Center analysis.

In addition to the heat advisory, officials issued an air quality alert for the Denver metro area and a red flag warning for hazardous fire conditions across a 13-county area in northeast Colorado. Both alerts will remain in effect through at least Thursday evening.

“Record heat and low humidity, very dry fuels, and breezy conditions means that rapid fire spread will be possible,” the National Weather Service said in an advisory.