Xcel Energy says about 290,000 of its customers in the Denver area lost electricity for a sustained period Wednesday thanks to a walloping spring storm that dropped several inches of heavy spring snow on power lines.

Power outages started about 4 a.m. and by about 9:30 p.m. about 51,500 remained without power, according to Xcel spokesman Mark Stutz . Crews planned to work until 11 p.m. Wednesday, before resuming at 7 a.m. Thursday.

Also on Thursday, out of state workers will arrive here to join Xcel crews, swelling the number of emergency repair workers to 800.

By Wednesday evening, main feeder line issues were resolved, leaving crews to tackle individual, secondary system outages, Stutz said.

At 3 p.m. Wednesday, about 90,000 were still without power as crews rushed to tackle as many problem areas as possible.

Workers from Oklahoma, New Mexico, Kansas and even as far away as Texas are expected to flood into Colorado on Thursday to help with repair efforts.

Power outages Wednesday were mainly in areas north of Denver, Stutz said. The number of impacted customers steadily rose by the thousands throughout the day.

“We’re starting to turn a corner — we hope — here,” Stutz said Wednesday afternoon.

Stutz said crews will be working well into Thursday to restore electricity, but cautioned that any hardened timeline for repairs remains premature.

As of 7 p.m., the number of Xcel outages was 1,492 affecting 79,179 customers.

Xcel is dealing with downed trees, swaying branches and high winds, he said. Many of the issues are in main distribution lines, which Stutz called the backbone of Xcel’s system.

“We really saw the problems starting early this morning in the Boulder area and then spreading,” Stutz said.

Denver International Airport was one of the impacted sites. The fuel tanks to the north side of DIA’s property for a while were without power, which also stopped trains and hindered the ability to pump fuel to the concourses.

Power at the hub has since been restored.

“We do have literally all hands on deck right now,” Stutz said. “There are 500-plus employees out there working to restore this as quickly as possible.”

MORE: Colorado snow totals for March 23, 2016

Other utilities are reporting power outages elsewhere along the Front Range.

In Brighton, city officials say United Power Inc. is experiencing weather-related problems.

Intermountain Rural Electric Association says its crews have been dispatched to outages in and around Bennett, Conifer and Deer Trail.

“We appreciate your patience as we work to restore service as quickly as possible,” the utility said in a statement on its website.

Poudre Valley REA said it was experiencing widespread outages from the storm.

Colorado Springs Utilities was reporting power loss to thousands of customers across its coverage area as well.

Jesse Paul: 303-954-1733, jpaul@denverpost.com or @JesseAPaul